bpo-30021: Add examples for re.escape(). (#1048) (#1115)

And fix the parameter name.

(cherry picked from commit 8fc7bc2b)

Doc/library/re.rst

@@ -784,11 +784,22 @@ 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

@@ -302,6 +302,8 @@ whatsnew/3.2,,:feed,>>> urllib.parse.urlparse('http://[dead:beef:cafe:5417:affe:
 whatsnew/3.2,,:gz,">>> with tarfile.open(name='myarchive.tar.gz', mode='w:gz') as tf:"
 whatsnew/3.2,,:location,zope9-location = ${zope9:location}
 whatsnew/3.2,,:prefix,zope-conf = ${custom:prefix}/etc/zope.conf
+library/re,,`,!#$%&'*+-.^_`|~:
+library/re,,`,\!\#\$\%\&\'\*\+\-\.\^_\`\|\~\:
 library/tarfile,,:xz,'x:xz'
 library/xml.etree.elementtree,,:sometag,prefix:sometag
 library/xml.etree.elementtree,,:fictional,"<actors xmlns:fictional=""http://characters.example.com"""