When $wgAdvancedSearchDeepcatEnabled is set to false, the search correctly uses the incategory: modifier instead of deepcategory:. However, the help dialog that appears when clicking the "info" button displays help about the deepcategory feature and not the incategory feature, which has some differences.

List of steps to reproduce (step by step, including full links if applicable):

1. On a wiki with this extension installed, set $wgAdvancedSearchDeepcatEnabled to false.
2. Go to Special:Search
3. Open "Advanced search", and click the button with an information icon on the "Pages in these categories" field.

What happens?:

The help text talks about the deepcategory feature: 5 subcategory levels, the help page points to Deepcategory, Syntax-equivalent in the normal search uses 'deepcategory:'

What should have happened instead?:

A different i18n message should be displayed instead, when deepcategory is disabled, providing help only about the incategory: feature and not deepcategory:

Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc.:

Tested on 1.37 but also happening on master branch.

See example: https://www.wikidex.net/index.php?title=Especial%3ABuscar&search=&fulltext=Buscar&uselang=en