Update list of translatable strings for MediaElement.js

[ocean90]

Our list isn't quite up to date, for example the "Play/Pause" string was separated in ​https://github.com/johndyer/mediaelement/commit/6facbbc5d7d0c48cb443e83c37f914d340fa8ca1.

List of strings: ​https://github.com/johndyer/mediaelement/blob/2.22.0/src/js/me-i18n-locale-en.js

[ocean90]

In 38089:

Media: Update list of translatable strings for MediaElement.js.

Fixes #37394.

[ocean90]

In 38090:

Media: Add missing gettext to a string added in [38089].

See #37394.

[SergeyBiryukov]

In 38150:

I18N: Add a translator comment for two MediaElement.js strings added in [38089].

Props ideag.
See #37453, #37394.

[johnbillion]

The Jump forward %1 seconds string doesn't exist. It looks like the jumpforward feature of MEP isn't included in WordPress.

This should either be included, or the unused string should be removed.

[nacin]

Yeah, we only include the default features. A bunch of them are not included by default, including jumpforward. This string should be removed. Someone including the plugin should include whatever strings they need.

[nacin]

In 38203:

MediaElement: Remove translated string from a plugin WP doesn't bundle.

fixes #37394.

[pento]

In 38204:

MediaElement: Remove translated string from a plugin WP doesn't bundle.

Merge of [38203] to the 4.6 branch.

Props nacin.
Fixes #37394.

[swissspidy]

In 40775:

Media: Correct a translatable string for MediaElement.js.

Adds the needed context to the string "None". Introduced in [38089].

Props leewillis77.
See #37394.
Fixes #40800.