docs: fix code comment formatting (#1153)

* docs(branch.rst): Line number comments not needed

The topic `Branch Coverage Management` in this file
already has a setting:

        :linenothreshold: 5

Using this setting, sphinx will automatically provide
line numbers for code block longer than 5 lines.

reference: https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html#directive-option-highlight-linenothreshold

* docs: Extra spaces in comment (maybe intentional)

The lines edited in this commit might have been given
extra indentation purposefully.
As they are an instruction for coverage py and are immediately
followed by another comment that is not for coveragepy.

* docs: inconsistent spaces in comments

Fix extra indentations or lack of indentations.

doc/branch.rst

@@ -17,10 +17,10 @@ and flags lines that haven't visited all of their possible destinations.
 
 For example::
 
-    def my_partial_fn(x):       # line 1
-        if x:                   #      2
-            y = 10              #      3
-        return y                #      4
+    def my_partial_fn(x):
+        if x:
+            y = 10
+        return y
 
     my_partial_fn(1)
 
@@ -78,7 +78,7 @@ as a branch if one of its choices is excluded::
         if x:
             blah1()
             blah2()
-        else:       # pragma: no cover
+        else:  # pragma: no cover
             # x is always true.
             blah3()
 
@@ -108,7 +108,7 @@ tell coverage.py that you don't want them flagged by marking them with a
 pragma::
 
     i = 0
-    while i < 999999999:    # pragma: no branch
+    while i < 999999999:  # pragma: no branch
         if eventually():
             break
 

doc/cmd.rst

@@ -517,7 +517,7 @@ For example::
 
     > def h(x):
           """Silly function."""
-    -     if 0:   #pragma: no cover
+    -     if 0:  # pragma: no cover
     -         pass
     >     if x == 1:
     !         a = 1

doc/excluding.rst

@@ -17,7 +17,7 @@ Coverage.py will look for comments marking clauses for exclusion.  In this
 code, the "if debug" clause is excluded from reporting::
 
     a = my_function1()
-    if debug:   # pragma: no cover
+    if debug:  # pragma: no cover
         msg = "blah blah"
         log_message(msg, a)
     b = my_function2()
@@ -32,7 +32,7 @@ function is not reported as missing::
             blah1()
             blah2()
 
-        def __repr__(self): # pragma: no cover
+        def __repr__(self):  # pragma: no cover
             return "<MyObject>"
 
 Excluded code is executed as usual, and its execution is recorded in the
@@ -50,7 +50,7 @@ counted as a branch if one of its choices is excluded::
         if x:
             blah1()
             blah2()
-        else:       # pragma: no cover
+        else:  # pragma: no cover
             # x is always true.
             blah3()