bpo-30021: Add examples for re.escape(). (#1048) (#1116)

And fix the parameter name.

(cherry picked from commit 8fc7bc2)

Author: serhiy-storchaka

Doc/library/re.rst

@@ -771,11 +771,22 @@ form.
       Unmatched groups are replaced with an empty string.
 
 
-.. function:: escape(string)
+.. function:: escape(pattern)
 
-   Escape all the characters in pattern except ASCII letters, numbers and ``'_'``.
+   Escape all the characters in *pattern* except ASCII letters, numbers and ``'_'``.
    This is useful if you want to match an arbitrary literal string that may
-   have regular expression metacharacters in it.
+   have regular expression metacharacters in it.  For example::
+
+      >>> print(re.escape('python.exe'))
+      python\.exe
+
+      >>> legal_chars = string.ascii_lowercase + string.digits + "!#$%&'*+-.^_`|~:"
+      >>> print('[%s]+' % re.escape(legal_chars))
+      [abcdefghijklmnopqrstuvwxyz0123456789\!\#\$\%\&\'\*\+\-\.\^_\`\|\~\:]+
+
+      >>> operators = ['+', '-', '*', '/', '**']
+      >>> print('|'.join(map(re.escape, sorted(operators, reverse=True))))
+      \/|\-|\+|\*\*|\*
 
    .. versionchanged:: 3.3
       The ``'_'`` character is no longer escaped.

Doc/tools/susp-ignored.csv

@@ -274,6 +274,8 @@ whatsnew/3.2,,:location,zope9-location = ${zope9:location}
 whatsnew/3.2,,:prefix,zope-conf = ${custom:prefix}/etc/zope.conf
 whatsnew/changelog,,:gz,": TarFile opened with external fileobj and ""w:gz"" mode didn't"
 whatsnew/changelog,,::,": Use ""127.0.0.1"" or ""::1"" instead of ""localhost"" as much as"
+library/re,,`,!#$%&'*+-.^_`|~:
+library/re,,`,\!\#\$\%\&\'\*\+\-\.\^_\`\|\~\:
 library/tarfile,149,:xz,'x:xz'
 library/xml.etree.elementtree,290,:sometag,prefix:sometag
 library/xml.etree.elementtree,301,:fictional,"<actors xmlns:fictional=""http://characters.example.com"""