[doc] configparser: avoid inline comments. (GH-31247)

People are testing those blocs with the default
inline_comment_prefixes of None, leading to a:

configparser.InterpolationSyntaxError: '$' must be followed by '$' or '{', found: '$ sign ($ is the only character that needs to be escaped)'
(cherry picked from commit 3ac4e78)

Co-authored-by: Julien Palard <[email protected]>

Author: miss-islington

Doc/library/configparser.rst

@@ -323,7 +323,8 @@ from ``get()`` calls.
       my_pictures: %(my_dir)s/Pictures
 
       [Escape]
-      gain: 80%%  # use a %% to escape the % sign (% is the only character that needs to be escaped)
+      # use a %% to escape the % sign (% is the only character that needs to be escaped):
+      gain: 80%%
 
    In the example above, :class:`ConfigParser` with *interpolation* set to
    ``BasicInterpolation()`` would resolve ``%(home_dir)s`` to the value of
@@ -358,7 +359,8 @@ from ``get()`` calls.
       my_pictures: ${my_dir}/Pictures
 
       [Escape]
-      cost: $$80  # use a $$ to escape the $ sign ($ is the only character that needs to be escaped)
+      # use a $$ to escape the $ sign ($ is the only character that needs to be escaped):
+      cost: $$80
 
    Values from other sections can be fetched as well: