Add template support for lang dropdown outside learn folders

[digitaldiina]

Is there an existing issue for this?

• [X] I have searched the existing issues

What kind of idea is it?

Usability

Description

After introducing the admin subfolder on entities and similar, help pages no longer having a learn parent folder do not show the language dropdown even when there are translations available.

These pages still have uid: help- in the frontmatter, which could be used as a criteria for showing the language drop-down instead of URL.

Anything else?

Use the recently updated custom-objects folder to explore behavior

[digitaldiina]

Can use "uid: help-" in frontmatter to test if it is a "learn" file