Enhanced documentation for "IgnoredMethods" option

This PR is documentation was added according to the following policy
for "IgnoredMethods" option

- Add code examples for cop that don't have code examples
- Add default values for cop that don't have default values

The code example also clearly shows the difference in behavior from
the default when the default for "IgnoredMethods" is an empty array.

lib/rubocop/cop/lint/ambiguous_block_association.rb

@@ -7,6 +7,7 @@ module Lint
       # when param passed without parentheses.
       #
       # This cop can customize ignored methods with `IgnoredMethods`.
+      # By default, there are no methods to ignored.
       #
       # @example
       #
@@ -29,10 +30,16 @@ module Lint
       #   # Lambda arguments require no disambiguation
       #   foo = ->(bar) { bar.baz }
       #
+      # @example IgnoredMethods: [] (default)
+      #
+      #   # bad
+      #   expect { do_something }.to change { object.attribute }
+      #
       # @example IgnoredMethods: [change]
       #
       #   # good
       #   expect { do_something }.to change { object.attribute }
+      #
       class AmbiguousBlockAssociation < Base
         include IgnoredMethods
 

lib/rubocop/cop/lint/number_conversion.rb

@@ -16,7 +16,8 @@ module Lint
       # NOTE: Some values cannot be converted properly using one of the `Kernel`
       # method (for instance, `Time` and `DateTime` values are allowed by this
       # cop by default). Similarly, Rails' duration methods do not work well
-      # with `Integer()` and can be ignored with `IgnoredMethods`.
+      # with `Integer()` and can be ignored with `IgnoredMethods`. By default,
+      # there are no methods to ignored.
       #
       # @safety
       #   Autocorrection is unsafe because it is not guaranteed that the
@@ -45,6 +46,11 @@ module Lint
       #   foo.try { |i| Float(i) }
       #   bar.send { |i| Complex(i) }
       #
+      # @example IgnoredMethods: [] (default)
+      #
+      #   # bad
+      #   10.minutes.to_i
+      #
       # @example IgnoredMethods: [minutes]
       #
       #   # good

lib/rubocop/cop/metrics/block_length.rb

@@ -15,6 +15,7 @@ module Metrics
       #
       # NOTE: The `ExcludedMethods` configuration is deprecated and only kept
       # for backwards compatibility. Please use `IgnoredMethods` instead.
+      # By default, there are no methods to ignored.
       #
       # @example CountAsOne: ['array', 'heredoc']
       #

lib/rubocop/cop/metrics/method_length.rb

@@ -13,6 +13,7 @@ module Metrics
       #
       # NOTE: The `ExcludedMethods` configuration is deprecated and only kept
       # for backwards compatibility. Please use `IgnoredMethods` instead.
+      # By default, there are no methods to ignored.
       #
       # @example CountAsOne: ['array', 'heredoc']
       #

lib/rubocop/cop/style/class_equality_comparison.rb

@@ -5,6 +5,8 @@ module Cop
     module Style
       # Enforces the use of `Object#instance_of?` instead of class comparison
       # for equality.
+      # `==`, `equal?`, and `eql?` methods are ignored by default.
+      # These are customizable with `IgnoredMethods` option.
       #
       # @example
       #   # bad
@@ -16,6 +18,26 @@ module Style
       #   # good
       #   var.instance_of?(Date)
       #
+      # @example IgnoreMethods: [] (default)
+      #   # good
+      #   var.instance_of?(Date)
+      #
+      #   # bad
+      #   var.class == Date
+      #   var.class.equal?(Date)
+      #   var.class.eql?(Date)
+      #   var.class.name == 'Date'
+      #
+      # @example IgnoreMethods: [`==`]
+      #   # good
+      #   var.instance_of?(Date)
+      #   var.class == Date
+      #   var.class.name == 'Date'
+      #
+      #   # bad
+      #   var.class.equal?(Date)
+      #   var.class.eql?(Date)
+      #
       class ClassEqualityComparison < Base
         include RangeHelp
         include IgnoredMethods

lib/rubocop/cop/style/format_string_token.rb

@@ -12,6 +12,7 @@ module Style
       # to encoded URLs or Date/Time formatting strings.
       #
       # This cop can be customized ignored methods with `IgnoredMethods`.
+      # By default, there are no methods to ignored.
       #
       # @example EnforcedStyle: annotated (default)
       #
@@ -61,6 +62,11 @@ module Style
       #   # good
       #   format('%06d', 10)
       #
+      # @example IgnoredMethods: [] (default)
+      #
+      #   # bad
+      #   redirect('foo/%{bar_id}')
+      #
       # @example IgnoredMethods: [redirect]
       #
       #   # good

lib/rubocop/cop/style/method_call_without_args_parentheses.rb

@@ -5,12 +5,24 @@ module Cop
     module Style
       # Checks for unwanted parentheses in parameterless method calls.
       #
+      # This cop can be customized ignored methods with `IgnoredMethods`.
+      # By default, there are no methods to ignored.
+      #
       # @example
       #   # bad
       #   object.some_method()
       #
       #   # good
       #   object.some_method
+      #
+      # @example IgnoredMethods: [] (default)
+      #   # bad
+      #   object.foo()
+      #
+      # @example IgnoredMethods: [foo]
+      #   # good
+      #   object.foo()
+      #
       class MethodCallWithoutArgsParentheses < Base
         include IgnoredMethods
         extend AutoCorrector

lib/rubocop/cop/style/numeric_predicate.rb

@@ -6,13 +6,16 @@ module Style
       # Checks for usage of comparison operators (`==`,
       # `>`, `<`) to test numbers as zero, positive, or negative.
       # These can be replaced by their respective predicate methods.
-      # The cop can also be configured to do the reverse.
+      # This cop can also be configured to do the reverse.
       #
-      # The cop disregards `#nonzero?` as its value is truthy or falsey,
+      # This cop can be customized ignored methods with `IgnoredMethods`.
+      # By default, there are no methods to ignored.
+      #
+      # This cop disregards `#nonzero?` as its value is truthy or falsey,
       # but not `true` and `false`, and thus not always interchangeable with
       # `!= 0`.
       #
-      # The cop ignores comparisons to global variables, since they are often
+      # This cop ignores comparisons to global variables, since they are often
       # populated with objects which can be compared with integers, but are
       # not themselves `Integer` polymorphic.
       #
@@ -23,29 +26,40 @@ module Style
       #
       # @example EnforcedStyle: predicate (default)
       #   # bad
-      #
       #   foo == 0
       #   0 > foo
       #   bar.baz > 0
       #
       #   # good
-      #
       #   foo.zero?
       #   foo.negative?
       #   bar.baz.positive?
       #
       # @example EnforcedStyle: comparison
       #   # bad
-      #
       #   foo.zero?
       #   foo.negative?
       #   bar.baz.positive?
       #
       #   # good
+      #   foo == 0
+      #   0 > foo
+      #   bar.baz > 0
+      #
+      # @example IgnoredMethods: [] (default) with EnforcedStyle: predicate
+      #   # bad
+      #   foo == 0
+      #   0 > foo
+      #   bar.baz > 0
       #
+      # @example IgnoredMethods: [==] with EnforcedStyle: predicate
+      #   # good
       #   foo == 0
+      #
+      #   # bad
       #   0 > foo
       #   bar.baz > 0
+      #
       class NumericPredicate < Base
         include ConfigurableEnforcedStyle
         include IgnoredMethods

lib/rubocop/cop/style/symbol_proc.rb

@@ -7,6 +7,8 @@ module Style
       #
       # If you prefer a style that allows block for method with arguments,
       # please set `true` to `AllowMethodsWithArguments`.
+      # respond_to , and `define_method?` methods are ignored by default.
+      # These are customizable with `IgnoredMethods` option.
       #
       # @safety
       #   This cop is unsafe because `proc`s and blocks work differently
@@ -68,6 +70,12 @@ module Style
       #     s.upcase # some comment
       #     # some comment
       #   end
+      #
+      # @example IgnoredMethods: [respond_to, define_method] (default)
+      #   # good
+      #   respond_to { |foo| foo.bar }
+      #   define_method(:foo) { |foo| foo.bar }
+      #
       class SymbolProc < Base
         include CommentsHelp
         include RangeHelp