Changing theme text don't works as documented

[qgustavor]

Motivation

The documentation on changing theme text don't works as documented in the readme and following the default theme.yml:

• _layouts/default.html#27: here site.data.theme.t.menu should be a string.
• _includes/search-form.html#L7 and _includes/search/lunr-search-scripts.html#L91: in those site.data.theme.t.menu is expected to be a hash.

Suggestion

Probably the search includes using t.menu.[...] are bugs, so just fix those.