its != it's (again)

[kitchin]

This is a follow-up to #22665. Doc fix only, for grammar/usage. More of the same issue as 22665, which was fixed and closed in 3.6.

Here is a patch for the following files. I can excise upstreams. Which ones should I take out?

src/wp-admin/includes/file.php
src/wp-admin/includes/image-edit.php
src/wp-includes/class-json.php
src/wp-includes/class-pop3.php
src/wp-includes/class-wp-http-streams.php
src/wp-includes/ID3/module.tag.id3v2.php
src/wp-includes/js/tinymce/tiny_mce_popup.js
src/wp-includes/js/tinymce/tinymce.js
src/wp-includes/SimplePie/Cache/Memcache.php
src/wp-includes/SimplePie/Item.php
src/wp-includes/wp-db.php
tests/phpunit/data/formatting/sizzle.js
tests/phpunit/tests/canonical.php
tests/phpunit/tests/mail.php
tests/qunit/editor/js/qunit/qunit.js
tests/qunit/editor/tinymce/dom/DomQuery.js

[kitchin]

Mostly replacing "it's" with "its" in the right places.

[SergeyBiryukov]

These ones can be patched:

src/wp-admin/includes/file.php
src/wp-admin/includes/image-edit.php
src/wp-includes/class-json.php
src/wp-includes/class-pop3.php
src/wp-includes/class-wp-http-streams.php
src/wp-includes/wp-db.php
tests/phpunit/tests/canonical.php
tests/phpunit/tests/mail.php

These ones should be taken upstream:

src/wp-includes/ID3/module.tag.id3v2.php
src/wp-includes/js/tinymce/tiny_mce_popup.js
src/wp-includes/js/tinymce/tinymce.js
src/wp-includes/SimplePie/Cache/Memcache.php
src/wp-includes/SimplePie/Item.php
tests/phpunit/data/formatting/sizzle.js
tests/qunit/editor/js/qunit/qunit.js
tests/qunit/editor/tinymce/dom/DomQuery.js

[kitchin]

same patch, excluding upstreams

[DrewAPicture]

In 34234:

Docs: Put "it's" in its place (again).

Props kitchin.
Fixes #33894.