Fix typo and spelling inconsistency in CONTRIBUTING.md

Fix spellings of GitHub

Remove unnecessary changes

Fix GitHub spelling on doc/translation_process.md

contrib/README.md

@@ -3,7 +3,7 @@ Repository Tools
 
 ### [Developer tools](/contrib/devtools) ###
 Specific tools for developers working on this repository.
-Contains the script `github-merge.py` for merging github pull requests securely and signing them using GPG.
+Contains the script `github-merge.py` for merging GitHub pull requests securely and signing them using GPG.
 
 ### [Verify-Commits](/contrib/verify-commits) ###
 Tool to verify that every merge commit was signed by a developer using the above `github-merge.py` script.

contrib/devtools/README.md

@@ -125,7 +125,7 @@ check or whatever).
 
 This means that there are no potential race conditions (where a
 pullreq gets updated while you're reviewing it, but before you click
-merge), and when using GPG signatures, that even a compromised github
+merge), and when using GPG signatures, that even a compromised GitHub
 couldn't mess with the sources.
 
 Setup