Expand documentation of cardinality methods.

By translating all other cardinality methods to the times method, we
clarify both that all the other methods are merely syntactic sugar, and
that they all set the lower and upper limits to the number of calls.

Closes freerange#476

lib/mocha/expectation.rb

@@ -17,7 +17,7 @@ module Mocha
   class Expectation
     # Modifies expectation so that the number of calls to the expected method must be within a specific +range+.
     #
-    # @param [Range,Integer] range specifies the allowable range in the number of expected invocations.
+    # @param [Range,Integer] range specifies the allowable number or range in the number of expected invocations.
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
     #
     # @example Specifying a specific number of expected invocations.
@@ -47,7 +47,7 @@ def times(range)
       self
     end
 
-    # Modifies expectation so that the expected method must be called exactly twice.
+    # Modifies expectation so that the expected method must be called exactly twice. Has the same effect as calling {times}(2).
     #
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
     #
@@ -72,7 +72,7 @@ def twice
       times(2)
     end
 
-    # Modifies expectation so that the expected method must be called exactly once.
+    # Modifies expectation so that the expected method must be called exactly once. Has the same effect as calling {times}(1).
     #
     # Note that this is the default behaviour for an expectation, but you may wish to use it for clarity/emphasis.
     #
@@ -96,7 +96,7 @@ def once
       times(1)
     end
 
-    # Modifies expectation so that the expected method must never be called.
+    # Modifies expectation so that the expected method must never be called. Has the same effect as calling {times}(0).
     #
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
     #
@@ -112,7 +112,8 @@ def never
       times(0)
     end
 
-    # Modifies expectation so that the expected method must be called at least a +minimum_number_of_times+.
+    # Modifies expectation so that the expected method must be called at least a +minimum_number_of_times+ and at most any number of times.
+    # Has the same effect as calling {times}(+minimum_number_of_times+..Float::INFINITY).
     #
     # @param [Integer] minimum_number_of_times minimum number of expected invocations.
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
@@ -132,7 +133,8 @@ def at_least(minimum_number_of_times)
       self
     end
 
-    # Modifies expectation so that the expected method must be called at least once.
+    # Modifies expectation so that the expected method must be called at least once and at most any number of times.
+    # Has the same effect as calling {at_least}(1).
     #
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
     #
@@ -149,7 +151,8 @@ def at_least_once
       at_least(1)
     end
 
-    # Modifies expectation so that the expected method must be called at most a +maximum_number_of_times+.
+    # Modifies expectation so that the expected method must be called from never to at most a +maximum_number_of_times+.
+    # Has the same effect as calling {times}(0..+maximum_number_of_times+).
     #
     # @param [Integer] maximum_number_of_times maximum number of expected invocations.
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
@@ -167,7 +170,8 @@ def at_most(maximum_number_of_times)
       times(0..maximum_number_of_times)
     end
 
-    # Modifies expectation so that the expected method must be called at most once.
+    # Modifies expectation so that the expected method must be called from never to at most once.
+    # Has the same effect as calling {at_most}(1).
     #
     # @return [Expectation] the same expectation, thereby allowing invocations of other {Expectation} methods to be chained.
     #