diff syntax highlighting not available in some Tomorrow themes

[jleclanche]

Reproduce:

1. Create a diff file. Use git show > foo.diff, or eg. copy the following to a new diff file:

diff --git a/.travis.yml b/.travis.yml
index ef975079..4585f88e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,13 +8,13 @@ addons:
   postgresql: "9.4"
 
 env:
-  - TOXENV=py27-django110
-  - TOXENV=py27-django111
-  - TOXENV=py34-django110
-  - TOXENV=py34-django111
-  - TOXENV=py35-django110
-  - TOXENV=py35-django111
-  - TOXENV=py36-django111
+  - TOXENV=py27-django110-jsonfield,py27-django110-bjson
+  - TOXENV=py27-django111-jsonfield,py27-django110-bjson
+  - TOXENV=py34-django110-jsonfield,py27-django110-bjson
+  - TOXENV=py34-django111-jsonfield,py27-django110-bjson
+  - TOXENV=py35-django110-jsonfield,py27-django110-bjson
+  - TOXENV=py35-django111-jsonfield,py27-django110-bjson
+  - TOXENV=py36-django111-jsonfield,py27-django110-bjson
   - TOXENV=flake8

The file will not be highlighted in the following color themes:

• Tomorrow
• Tomorrow Night
• Tomorrow Night Bright
• Tomorrow Night Eighties

The file is correctly highlighted in Tomorrow Night Blue.