[Core] Support change of scoring algorithm/similarity at the hidden _category_name field level

[rbayet]

PR #3712 introduces the ability to

• change the scoring algorithm ("similarity") at the attribute level in their advanced properties
• change the scoring algorithm for the collector fields ("search", "spelling", etc) through a Stores > Configuration setting

What might be missing is an additional setting to change it also for the _category_name field which is used when someone wants to boost hits in the products' category names.
My guess would be an additional / specific Stores Configuration setting, located just below the "Category Name Weight", and visible when the search weight is greater than 1 (I know how to do this in PHP with the DependencyFieldFactory but not sure how it can be done in system.xml) and re-using (most of) the wording of the other existing setting.

Ideal location in Stores > Configuration > Elasticsuite > Catalog Search > Catalog Search Configuration, below this field

The existing configuration field (down at the bottom of this section)

[romainruaud]

Agreed, but I think it's a low risk (therefore low priority) because it's unlikely that a category name will contain X times a word, no ?