Categorize documentations

Once DevDocs supports a few more documentations it may be a good idea to organize the "Select documentation" list by "kind" or programming language.

The issue names only the “Select documentation” list and provides no file or test path. Start by locating the code that renders and populates that list, then clarify whether grouping should use documentation kind, programming language, or both; done means the supported entries are organized consistently and the relevant UI behavior is covered by tests if they exist.

Scritto dal modello di indicizzazione a partire dal testo della issue.