♿ Apply lang="en" to relevant snippets in extensions/

[caroqliu]

This PR is a partial copy of #31208, which adds lang="en" to relevant code snippets in this codebase. Instead of copying the PR file-for-file, I decided to break this change up into a few root directories for ease of review and less likelihood of falling behind to merge conflicts. /to @banaag who approved the original PR

Original PR description:

Suggested changes and additions based on the TetraLogical accessibility review commissioned by @nainar / @caroqliu

x-ref ampproject/amp.dev#4972

Others in the series: #34757 #34758 #34759
/cc @TetraLogicalHelpdesk

[amp-owners-bot]

Hey @ampproject/wg-caching! These files were changed:

extensions/amp-3d-gltf/0.1/test/validator-amp-3d-gltf.html
extensions/amp-3d-gltf/0.1/test/validator-amp-3d-gltf.out
extensions/amp-access-laterpay/0.1/test/validator-amp-access-laterpay.html
extensions/amp-access-laterpay/0.1/test/validator-amp-access-laterpay.out
extensions/amp-access-laterpay/0.2/test/validator-amp-access-laterpay.html
extensions/amp-access-laterpay/0.2/test/validator-amp-access-laterpay.out
extensions/amp-access-poool/0.1/test/validator-amp-access-poool.html
extensions/amp-access-poool/0.1/test/validator-amp-access-poool.out
extensions/amp-access-scroll/0.1/test/validator-amp-access-scroll.html
extensions/amp-access-scroll/0.1/test/validator-amp-access-scroll.out
extensions/amp-access/0.1/test/validator-amp-access-missing-extension.html
extensions/amp-access/0.1/test/validator-amp-access-missing-extension.out
+418 more

Hey @gmajoulet! These files were changed:

extensions/amp-story-360/0.1/test/validator-amp-story-360.html
extensions/amp-story-360/0.1/test/validator-amp-story-360.out
extensions/amp-story-auto-analytics/0.1/test/validator-amp-story-auto-analytics.html
extensions/amp-story-auto-analytics/0.1/test/validator-amp-story-auto-analytics.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-poll.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-poll.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-quiz.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-quiz.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-results.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-results.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-valid.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-valid.out
+68 more

Hey @processprocess! These files were changed:

extensions/amp-story-360/0.1/test/validator-amp-story-360.html
extensions/amp-story-360/0.1/test/validator-amp-story-360.out
extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.html
extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out

Hey @t0mg! These files were changed:

extensions/amp-story-360/0.1/test/validator-amp-story-360.html
extensions/amp-story-360/0.1/test/validator-amp-story-360.out

Hey @mszylkowski! These files were changed:

extensions/amp-story-auto-analytics/0.1/test/validator-amp-story-auto-analytics.html
extensions/amp-story-auto-analytics/0.1/test/validator-amp-story-auto-analytics.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-poll.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-poll.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-quiz.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-quiz.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-results.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-results.out
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-valid.html
extensions/amp-story-interactive/0.1/test/validator-amp-story-interactive-valid.out

Hey @newmuis! These files were changed:

extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.html
extensions/amp-story-panning-media/0.1/test/validator-amp-story-panning-media.out
extensions/amp-story-player/0.1/test/validator-amp-story-player-error.html
extensions/amp-story-player/0.1/test/validator-amp-story-player-error.out
extensions/amp-story-player/0.1/test/validator-amp-story-player-img-error.html
extensions/amp-story-player/0.1/test/validator-amp-story-player-img-error.out
extensions/amp-story-player/0.1/test/validator-amp-story-player-img.html
extensions/amp-story-player/0.1/test/validator-amp-story-player-img.out
extensions/amp-story-player/0.1/test/validator-amp-story-player.html
extensions/amp-story-player/0.1/test/validator-amp-story-player.out
extensions/amp-story/1.0/test/validator-amp-story-360.html
extensions/amp-story/1.0/test/validator-amp-story-360.out
+56 more

[Gregable]

I'm not opposed, but these are all test files for validator, not examples. They aren't documentation (tests are partially documentation, but not in the way this is being applied).

You've already made the changes, so go ahead, but I would recommend saving the trouble in future cases of this.

[caroqliu]

I'm not opposed, but these are all test files for validator, not examples. They aren't documentation (tests are partially documentation, but not in the way this is being applied).

You've already made the changes, so go ahead, but I would recommend saving the trouble in future cases of this.

Thanks for the recommendation—I tend to agree and will keep an eye out for similar changes in the future that may not be worth the trouble.