develwarn: move config gating inside the develwarn function

The config gating is almost always the same and contributor tend to forget it.
We move the logic inside the function. Call site will be updated in later
changeset. We might make the sub config mandatory in the future (once all old
call sites are gone).

mercurial/ui.py

@@ -1135,12 +1135,15 class ui(object):
         '''
         return msg
 
-    def develwarn(self, msg, stacklevel=1):
+    def develwarn(self, msg, stacklevel=1, config=None):
         """issue a developer warning message
 
         Use 'stacklevel' to report the offender some layers further up in the
         stack.
         """
+        if not self.configbool('devel', 'all-warnings'):
+            if config is not None and not self.configbool('devel', config):
+                return
         msg = 'devel-warn: ' + msg
         stacklevel += 1 # get in develwarn
         if self.tracebackflag: