Adds button to show diff (or patch) file for commit
Adds a button to show the .diff file for every commit.
Hold Shift key to open the .patch file instead of an .diff file.
This works on commits, pull requests and compare pages.
Tampermonkey on 
Mozilla Firefox desktop.1.6.7
1.6.6
.patch was broken (fixes 119).1.6.5
1.6.4
1.6.3
1.6.2
1.6.1
1.6
1.5
1.4
1.3
1.2
1.1
1.0
Use cases:
https://github.com/OpenUserJs/OpenUserJS.org/commit/aac291b83a5d5fa4fb4382080473ef3a4dd908c2 (commit)
https://github.com/OpenUserJs/OpenUserJS.org/pull/327/files (PR)
https://github.com/OpenUserJs/OpenUserJS.org/pull/327/commits/aac291b83a5d5fa4fb4382080473ef3a4dd908c2 (PR commit)
https://github.com/OpenUserJs/OpenUserJS.org/compare/master%40%7B1day%7D...master (compare)