Make tree-sitter font-lock support decoration levels

* admin/notes/tree-sitter/html-manual/Parser_002dbased-Font-Lock.html:
Update.
* admin/notes/tree-sitter/html-manual/Parsing-Program-Source.html:
Update.
* doc/lispref/modes.texi: Mention the new :level option.
* lisp/treesit.el (treesit-font-lock-settings): Update docstring.
(treesit-font-lock-rules): Support :level.  Relayout the let form.
(treesit-font-lock-fontify-region): Support :level.

1 files changed, 4 insertions, 0 deletions

diff --git a/admin/notes/tree-sitter/html-manual/Parsing-Program-Source.html b/admin/notes/tree-sitter/html-manual/Parsing-Program-Source.html
index 7b6e51468a6..81b42f7f526 100644
--- a/admin/notes/tree-sitter/html-manual/Parsing-Program-Source.html
+++ b/admin/notes/tree-sitter/html-manual/Parsing-Program-Source.html
@@ -94,6 +94,10 @@ for this Emacs instance.
 see <a href="Parser_002dbased-Font-Lock.html">Parser-based Font Lock</a>, <a href="Parser_002dbased-Indentation.html">Parser-based Indentation</a>, and
 <a href="List-Motion.html">Moving over Balanced Expressions</a>.
 </p>
+<p>About naming convention: use &ldquo;tree-sitter&rdquo; when referring to it as a
+noun, like <code>python-use-tree-sitter</code>, but use &ldquo;treesit&rdquo; for
+prefixes, like <code>python-treesit-indent-function</code>.
+</p>
 <p>To access the syntax tree of the text in a buffer, we need to first
 load a language definition and create a parser with it.  Next, we can
 query the parser for specific nodes in the syntax tree.  Then, we can