docs: fix vim.treesitter tags

Problem:
Help tags like vim.treesitter.language.add() are confusing because
`vim.treesitter.language` is (thankfully) not a user-facing module.

Solution:
Ignore the "fstem" when generating "treesitter" tags.

runtime/lua/vim/treesitter/highlighter.lua

@@ -58,7 +58,9 @@ function TSHighlighterQuery:query()
   return self._query
 end
 
---- Creates a new highlighter using @param tree
+---@private
+---
+--- Creates a highlighter for `tree`.
 ---
 ---@param tree LanguageTree parser object to use for highlighting
 ---@param opts (table|nil) Configuration of the highlighter:

runtime/lua/vim/treesitter/languagetree.lua

@@ -38,18 +38,16 @@ local LanguageTree = {}
 
 LanguageTree.__index = LanguageTree
 
---- A |LanguageTree| holds the treesitter parser for a given language {lang} used
---- to parse a buffer. As the buffer may contain injected languages, the LanguageTree
---- needs to store parsers for these child languages as well (which in turn may contain
---- child languages themselves, hence the name).
+--- @private
 ---
----@param source (integer|string) Buffer or a string of text to parse
----@param lang string Root language this tree represents
----@param opts (table|nil) Optional keyword arguments:
----             - injections table Mapping language to injection query strings.
----                                This is useful for overriding the built-in
----                                runtime file searching for the injection language
----                                query per language.
+--- |LanguageTree| contains a tree of parsers: the root treesitter parser for {lang} and any
+--- "injected" language parsers, which themselves may inject other languages, recursively.
+---
+---@param source (integer|string) Buffer or text string to parse
+---@param lang string Root language of this tree
+---@param opts (table|nil) Optional arguments:
+---             - injections table Map of language to injection query strings. Overrides the
+---                                built-in runtime file searching for language injections.
 ---@return LanguageTree parser object
 function LanguageTree.new(source, lang, opts)
   language.add(lang)

runtime/lua/vim/treesitter/query.lua

@@ -273,8 +273,7 @@ end
 ---@param opts (table|nil) Optional parameters.
 ---          - concat: (boolean) Concatenate result in a string (default true)
 ---          - metadata (table) Metadata of a specific capture. This would be
----            set to `metadata[capture_id]` when using
----            |vim.treesitter.query.add_directive()|.
+---            set to `metadata[capture_id]` when using |vim.treesitter.add_directive()|.
 ---@return (string[]|string|nil)
 function M.get_node_text(node, source, opts)
   opts = opts or {}
@@ -486,7 +485,7 @@ local directive_handlers = {
 ---
 ---@param name string Name of the predicate, without leading #
 ---@param handler function(match:table<string,TSNode>, pattern:string, bufnr:number, predicate:string[])
----   - see |vim.treesitter.query.add_directive()| for argument meanings
+---   - see |vim.treesitter.add_directive()| for argument meanings
 ---@param force boolean|nil
 function M.add_predicate(name, handler, force)
   if predicate_handlers[name] and not force then