Do not hardcode script languages path for themes

[swissspidy]

The change in https://core.trac.wordpress.org/ticket/60891 / https://core.trac.wordpress.org/changeset/57922 was not tested enough with themes that load script translations. It caused a regression where WP tried to look up script translations for a theme in wp-content/languages/plugins.

Even when using a custom WP_PLUGIN_DIR/WP_PLUGIN_URL configuration, we should always use the correct path for themes and plugins alike.

To-do:

• Add unit tests

Trac ticket: https://core.trac.wordpress.org/ticket/62016

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[swissspidy]

Committed in https://core.trac.wordpress.org/changeset/59126

[them-es]

@swissspidy Could you have a look at whether this is a viable alternative approach?

Replace the changes in this commit with only the following line:
Line 1210 $languages_path = WP_LANG_DIR . '/' . $relative[0];

At least this fixes a regression reported 2 weeks ago: https://core.trac.wordpress.org/ticket/62155

[swissspidy]

No, this just reintroduces the original bug.

[swissspidy]

@them-es #7562 should address this, please test

[them-es]

@swissspidy Yes that seems to fix the reported Multisite regression. Thank you for the quick turnaround 👍