Merge branch '3.1.x' into 3.2.x
* 3.1.x: (46 commits)
Minor revisions
Minor revisions
Minor revisions
Minor revisions
Minor revisions
Typo fixes
Minor revisions
Minor revisions
Fix forgotten links
Copy Git docs over from the wiki
Update naming conventions
Spelling fixes
Clarify form key names
Clarify auth parameters for extensions
Minor corrections
Fix typo
Fix tabs into spaces
Update links to other doc files
Update all index links
Add new doc - Tutorial events
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