fix(lsp): filetype matching to documentSelector in dynamic capabilities (#25425)

Use the get_language_id client option to resolve the filetype when
matching the document selector in a dynamic capability.


Co-authored-by: Mathias Fussenegger <f.mathias@zignar.net>

runtime/lua/vim/lsp.lua

@@ -1073,7 +1073,7 @@ function lsp.start_client(config)
     end
 
     --- @param method string
-    --- @param opts? {bufnr?: number}
+    --- @param opts? {bufnr: integer?}
     client.supports_method = function(method, opts)
       opts = opts or {}
       local required_capability = lsp._request_name_to_capability[method]