commit: optionally strip quotes from commit template (BC)

For consistency with the other template options.

mercurial/cmdutil.py

@@ -2768,6 +2768,7 b' def commitforceeditor(repo, ctx, subs, f'
     while forms:
         tmpl = repo.ui.config('committemplate', '.'.join(forms))
         if tmpl:
+            tmpl = templater.unquotestring(tmpl)
             templatetext = committext = buildcommittemplate(
                 repo, ctx, subs, extramsg, tmpl)
             break

tests/test-commit.t

@@ -387,12 +387,12 b' specific template keywords work well'
 
   $ cat >> .hg/hgrc <<EOF
   > [committemplate]
-  > changeset.commit.normal = HG: this is "commit.normal" template
+  > changeset.commit.normal = 'HG: this is "commit.normal" template
   >     HG: {extramsg}
   >     {if(activebookmark,
   >    "HG: bookmark '{activebookmark}' is activated\n",
   >    "HG: no bookmark is activated\n")}{subrepos %
-  >    "HG: subrepo '{subrepo}' is changed\n"}
+  >    "HG: subrepo '{subrepo}' is changed\n"}'
   > 
   > changeset.commit = HG: this is "commit" template
   >     HG: {extramsg}