minirst: handle edge in hunting for parents

test for "hg help -c config" in help config

``section``
-----------
section text

``def1``
    definition of def1
    $ hg help scope.def1
    should list this paragraph, but not section text below...

section text

``def2``
    definition of def2
    $ hg help scope.def2
    should list this paragraph, but not section text below...

section text
$ hg help scope.section should show everything from the first
section text to this last line.

``section2``
------------

mercurial/minirst.py

@@ -741,7 +741,10 b' def getsections(blocks):'
                             break
                     pointer += 1
                 if pointer > 1:
-                    secs.append(('', secs[-pointer][1] + 1, []))
+                    blevel = secs[-pointer][1]
+                    if section['type'] != b['type']:
+                        blevel += 1
+                    secs.append(('', blevel, []))
             secs[-1][2].append(b)
     return secs
 

tests/test-help.t

@@ -922,6 +922,11 b' Test repeated config section name'
       "smtp.host"
           Host name of mail server, e.g. "mail.example.com".
   
+Unrelated trailing paragraphs shouldn't be included
+
+  $ hg help config.extramsg | grep '^$'
+  
+
 Test capitalized section name
 
   $ hg help scripting.HGPLAIN > /dev/null