[PATCH 4 of 4 evolve-ext] evolve: use registrar.templatekeyword to register template keyword functions

[FUJIWARA Katsunori]

# HG changeset patch
# User FUJIWARA Katsunori <foozy at lares.dti.ne.jp>
# Date 1502115761 -32400
#      Mon Aug 07 23:22:41 2017 +0900
# Node ID d24bf49080b751520b734482936566da7421de12
# Parent  dea894973e8faddafe06cc53fbfe6a4f109c3143
# Available At https://foozy@bitbucket.org/foozy/hgext-evolve
#              hg pull https://foozy@bitbucket.org/foozy/hgext-evolve -r d24bf49080b7
# EXP-Topic doc-improvement
evolve: use registrar.templatekeyword to register template keyword functions

Now, using registrar.templatekeyword of Mercurial directly in evolve
extension should be safe enough. because it has been available since
Mercurial 3.8, and minimum Mercurial version for evolve extension is
3.8, too.

BTW, this also fixes an issue of "hg help templates" output that
template keywords "precursors" and "successors" are not displayed as
same as others, because they do not have ":KEYWORD:" prefix in their
docstring.

diff --git a/hgext3rd/evolve/exthelper.py b/hgext3rd/evolve/exthelper.py
--- a/hgext3rd/evolve/exthelper.py
+++ b/hgext3rd/evolve/exthelper.py
@@ -99,8 +99,11 @@ class exthelper(object):
             revsetpredicate(name)(symbol)
         revset.loadpredicate(ui, 'evolve', revsetpredicate)
 
+        templatekeyword = registrar.templatekeyword()
         for name, kw in self._templatekws:
-            templatekw.keywords[name] = kw
+            templatekeyword(name)(kw)
+        templatekw.loadkeyword(ui, 'evolve', templatekeyword)
+
         for ext, command, wrapper, opts in self._extcommandwrappers:
             if ext not in knownexts:
                 try:
diff --git a/hgext3rd/evolve/templatekw.py b/hgext3rd/evolve/templatekw.py
--- a/hgext3rd/evolve/templatekw.py
+++ b/hgext3rd/evolve/templatekw.py
@@ -28,7 +28,7 @@ eh = exthelper.exthelper()
 
 @eh.templatekw('obsolete')
 def obsoletekw(repo, ctx, templ, **args):
-    """:obsolete: String. Whether the changeset is ``obsolete``.
+    """String. Whether the changeset is ``obsolete``.
     """
     if ctx.obsolete():
         return 'obsolete'
@@ -36,7 +36,7 @@ def obsoletekw(repo, ctx, templ, **args)
 
 @eh.templatekw('troubles')
 def showtroubles(**args):
-    """:troubles: List of strings. Evolution troubles affecting the changeset
+    """List of strings. Evolution troubles affecting the changeset
     (zero or more of "unstable", "divergent" or "bumped")."""
     ctx = args['ctx']
     try: