Merge branch 'refs' into docs-next

Tom Saeger says:

Recently, while reading up on binfmt I attempted to open a document ref
only to find it was invalid.  I did a quick grep, found all the
binfmt_misc related broken refs and sent a patch.

Fine. Easy.

Then I wondered, "how many broken doc refs are there?".

Turns out with all the recent doc moves, quite a few.

I went about fixing just those found in Documentation/,
except those in Documentation/translations/ and
Documentation/devicetree/ for now.

Most of these changes were s/txt/rst/ or fixing up a path to an obvious
new location.  Some required going back to v4.10 v4.4 or some other
version to sleuth-out what content was actually being referenced and
then fixing the reference to point to the new file with that content.