releasenotes: view admonition titles using -l flag

Since this extension is fairly new for almost all the contributors, remembering
the admonition (with titles) is difficult. The list (-l) flag provides
a list of all the active admonitions along with titles.

For usage, hg releasenotes -l returns the list.

Differential Revision: https://phab.mercurial-scm.org/D454

hgext/releasenotes.py

@@ -275,6 +275,10 b' def checkadmonitions(ui, repo, directive'
                     ss = ", ".join(sorted(similar))
                     ui.write(_("(did you mean one of %s?)\n") % ss)
 
+def _getadmonitionlist(ui, sections):
+    for section in sections:
+        ui.write("%s: %s\n" % (section[0], section[1]))
+
 def parsenotesfromrevisions(repo, directives, revs):
     notes = parsedreleasenotes()
 
@@ -467,7 +471,9 b' def serializenotes(sections, notes):'
 @command('releasenotes',
     [('r', 'rev', '', _('revisions to process for release notes'), _('REV')),
     ('c', 'check', False, _('checks for validity of admonitions (if any)'),
-        _('REV'))],
+        _('REV')),
+    ('l', 'list', False, _('list the available admonitions with their title'),
+        None)],
     _('hg releasenotes [-r REV] [-c] FILE'))
 def releasenotes(ui, repo, file_=None, **opts):
     """parse release notes from commit messages into an output file
@@ -546,8 +552,10 b' def releasenotes(ui, repo, file_=None, *'
     release note after it has been added to the release notes file.
     """
     sections = releasenotessections(ui, repo)
+    if opts.get('list'):
+        return _getadmonitionlist(ui, sections)
+
     rev = opts.get('rev')
-
     revs = scmutil.revrange(repo, [rev or 'not public()'])
     if opts.get('check'):
         return checkadmonitions(ui, repo, sections.names(), revs)

tests/test-releasenotes-formatting.t

@@ -407,3 +407,16 b' Suggest similar admonition in place of t'
   $ hg releasenotes -r . -c
   Invalid admonition 'fixes' present in changeset 0e7130d2705c
   (did you mean fix?)
+
+  $ cd ..
+
+Usage of --list flag
+
+  $ hg init relnotes-list
+  $ cd relnotes-list
+  $ hg releasenotes -l
+  feature: New Features
+  bc: Backwards Compatibility Changes
+  fix: Bug Fixes
+  perf: Performance Improvements
+  api: API Changes