Dont show highlighting warning in 1.3.x. This is a "feature-like" change.

CHANGES

@@ -20,6 +20,7 @@ Bugs fixed
   support parsers that specified source_parsers.
 * #2290: Fix ``sphinx.ext.mathbase`` use of amsfonts may break user choice of math fonts
 * #2324: Print a hint how to increase the recursion limit when it is hit.
+* #1565: Revert new warning; the new warning will be triggered from version 1.4 on.
 
 
 Release 1.3.5 (released Jan 24, 2016)

sphinx/highlighting.py

@@ -186,9 +186,7 @@ class PygmentsBridge(object):
         except ErrorToken as exc:
             # this is most probably not the selected language,
             # so let it pass unhighlighted
-            if warn:
-                warn('Could not parse literal_block as "%s". highlighting skipped.' % lang)
-            else:
+            if not warn:
                 raise exc
             hlsource = highlight(source, lexers['none'], formatter)
         if self.dest == 'html':