Repair various invalid escape sequences

Python 3.8 warns about invalid escape sequences. Replace occurrences with
valid equivalents.

Signed-off-by: Peter Grayson <[email protected]>

Author: jpgrayson

stgit/commands/id.py

@@ -25,7 +25,7 @@
 help = 'Print the git hash value of a StGit reference'
 kind = 'repo'
 usage = ['[options] [--] [<id>]']
-description = """
+description = r"""
 Print the SHA1 value of a Git id (defaulting to HEAD). In addition to the
 standard Git id's like heads and tags, this command also accepts
 '[<branch>:]<patch>' for the id of a patch, '[<branch>:]\{base\}' for the base

stgit/commands/mail.py

@@ -412,7 +412,7 @@ def __get_signers_list(msg):
     for line in msg.split('\n'):
         m = r.match(line)
         if m:
-            addr_list.append(m.expand('\g<2>'))
+            addr_list.append(m.expand(r'\g<2>'))
 
     return addr_list
 

stgit/completion.py

@@ -64,7 +64,7 @@ def util():
          fun('_stg_branches',
              'local g=$(_gitdir)', 'test "$g" && (cd $g/patches/ && echo *)'),
          fun('_mail_aliases',
-             'git config --name-only --get-regexp "^mail\.alias\." | cut -d. -f 3'),
+             'git config --name-only --get-regexp "^mail\\.alias\\." | cut -d. -f 3'),
          ref_list_fun('_all_branches', 'refs/heads'),
          ref_list_fun('_tags', 'refs/tags'),
          ref_list_fun('_remotes', 'refs/remotes')]