Also checks mediatype suffix for lexer in HttpLexer

The HttpLexer will highlight the body if the Content-Type header is set to a
mediatype that pygments understands. However, some mediatypes have a custom
subtype but a standard and known suffix. Therefore, pygments should highlight
body by the exact media type first and then by the suffix if there was no
match.

For example:

application/vnd.custom+json

currently does not result in the body being highlighted even though pygments is
capable

application/json

1 files changed, 10 insertions, 0 deletions

diff --git a/pygments/lexers/textfmts.py b/pygments/lexers/textfmts.py
index e3700e9f..04222562 100644
--- a/pygments/lexers/textfmts.py
+++ b/pygments/lexers/textfmts.py
@@ -154,6 +154,16 @@ class HttpLexer(RegexLexer):
                 for idx, token, value in lexer.get_tokens_unprocessed(content):
                     yield offset + idx, token, value
                 return
+            # Check for with just the suffix
+            content_type = re.sub(r'^(.*)/.*\+(.*)$', r'\1/\2', content_type)
+            try:
+                lexer = get_lexer_for_mimetype(content_type)
+            except ClassNotFound:
+                pass
+            else:
+                for idx, token, value in lexer.get_tokens_unprocessed(content):
+                    yield offset + idx, token, value
+                return
         yield offset, Text, content
 
     tokens = {