check-code: check comment for '.. note::' without two newlines

Because string entries are replaced before matching, we must search for
the transformed pattern. But it seems to be quite unique and does not return
false matches. If it will, they can be listed as 3rd arg in pypats.

contrib/check-code.py

@@ -263,6 +263,7 b' pypats = ['
   ],
   # warnings
   [
+    (r'(^| )oo +xxxxoo[ \n][^\n]', "add two newlines after '.. note::'"),
   ]
 ]
 

tests/test-check-code.t

@@ -204,3 +204,42 b''
    don't use old-style two-argument raise, use Exception(message)
   [1]
 
+  $ cat > rst.py <<EOF
+  > """problematic rst text
+  > 
+  > .. note::
+  >     wrong
+  > """
+  > 
+  > '''
+  > 
+  > .. note::
+  > 
+  >     valid
+  > 
+  > new text
+  > 
+  >     .. note::
+  > 
+  >         also valid
+  > '''
+  > 
+  > """mixed
+  > 
+  > .. note::
+  > 
+  >   good
+  > 
+  >     .. note::
+  >         plus bad
+  > """
+  > EOF
+  $ $check_code -w rst.py
+  rst.py:3:
+   > .. note::
+   warning: add two newlines after '.. note::'
+  rst.py:26:
+   >     .. note::
+   warning: add two newlines after '.. note::'
+  [1]
+