Cleanup some docs (languages)

- Makes beginning of @param in capital
- Removed return void

Change-Id: Ie05436c1ef886cb23c62ccde95384f253f83694c
Introduce SkinFactory

Modeled similar to ConfigFactory, this lets skins
register themselves via a callback, allowing for
proper dependency injection.

Loading via $wgValidSkinNames is still supported,
but considered "legacy", not deprecated though.

Skin::newFromKey is now deprecated (and had only
one caller in an extension, which I'll update
afterwards).

Change-Id: I1960483f87c2ef55c994545239b728fa376f17f4
Merge "Introduce SkinFactory"
Merge "Cleanup some docs (maintenance)"
Merge "Cleanup some docs (languages)"
Remove some unnecessary IE 6 hacks

We dropped JS support for IE 6. These workarounds for its bugs are no
longer necessary, because this code is no longer loaded. (The CSS
files modified are parts of modules that require JS support.)

We probably have a lot more, these just came up when grepping for
'IE6' and were obvious.

Change-Id: I7588b03f6ade699ddda4ec28be6c6f512e4b0ea8
Move Vector's hooks documentation to mediawiki/skins/Vector

Change-Id: Ide133c1ec0ae701c5864edcbab428be314bd159e
Never display empty sections on Special:Version

Follow-up to d423112b.

Change-Id: I44c8bfe6f4ca1350a7e35a253785f772602353c1
Merge "Never display empty sections on Special:Version"
Skin: Don't double-check for non-existing skin in newFromKey()

normalizeKey() should have already handled this.

Change-Id: Idf2510ec86841ed18d589f392a30db1b41ac0c24
Merge "Skin: Don't double-check for non-existing skin in newFromKey()"
Fix documentation for Html::closeElement

Follow-up to d950da075dcb6c6dd3f68a50a0d427569350763a

Change-Id: I916052cf924dd3c6664b6d7d02175fd74a71527b
Merge "Make styleguide mobile first"
Require a ResourceLoader instance is passed to ResourceLoaderContext

Change-Id: Ie1e5453b47349fc00664325827f88a1e7a6de43f
Fix userrights-interwiki when the 'user' table is shared

At present, this function selects the user table from the same DB as the
user_groups, however, in wikifarms this is not often the case, as the user
table is often shared, but the user_groups table not. Adding a check in
here, and passing the shared table, if needed, ONLY to the user query,
should fix.

Change-Id: Ib85630067c402b8e4f50ff11a33fe7f0eadd4f16
Merge "API: Remove action=paraminfo 'props' and 'errors' result properties"
Localisation updates from https://translatewiki.net.

Change-Id: I5529c6d8115cc05b3de8d3fde9de948f1719bed3
Do not allow a user to delete a page they can't edit

This was probably overlooked in the past because usually the only users
who can delete pages also have permission to edit the relevant
protection levels.

Change-Id: Ibe28a69c9fbab00b81c53b1643df722a3f1fbf19
Merge "Do not allow a user to delete a page they can't edit"
Add release notes for Ibe28a69c9fbab00b81c53b1643df722a3f1fbf19

Change-Id: I0a2b2feafcf2561369145bec80ec14c7929beff9