help: hide deprecated filesets, revsets and template items if not verbose

This allows us to hide {branches} template keyword in a better way. Currently
it is achieved by copying keywords table and deleting 'branches' from it.

mercurial/help.py

@@ -191,7 +191,8 b' def makeitemsdoc(ui, topic, doc, marker,'
     entries = []
     for name in sorted(items):
         text = (items[name].__doc__ or '').rstrip()
-        if not text:
+        if (not text
+            or not ui.verbose and any(w in text for w in _exclkeywords)):
             continue
         text = gettext(text)
         if dedent:

tests/test-help.t

@@ -980,6 +980,12 b' Test templating help'
       firstline     Any text. Returns the first line of text.
       nonempty      Any text. Returns '(none)' if the string is empty.
 
+Test deprecated items
+
+  $ hg help -v templating | grep currentbookmark
+      currentbookmark
+  $ hg help templating | (grep currentbookmark || true)
+
 Test help hooks
 
   $ cat > helphook1.py <<EOF