Make c-ts-common--fill-paragraph work for rust line comment

* lisp/progmodes/c-ts-common.el (c-ts-common--fill-paragraph): Back to
BOL before checking for //.

(cherry picked from commit 67ef1d54e7e3983bb03840cf8f2990d579942710)

diff --git a/lisp/progmodes/c-ts-common.el b/lisp/progmodes/c-ts-common.el
index 457aa55c195216bb4c55be899996255ff07e8cbe..c06295b8a87ea5a4736223a9a791bdb38bdd05f3 100644 (file)
--- a/lisp/progmodes/c-ts-common.el
+++ b/lisp/progmodes/c-ts-common.el
@@ -125,6 +125,9 @@ ARG is passed to `fill-paragraph'."
                             (treesit-node-type node))
         (if (save-excursion
               (goto-char (treesit-node-start node))
+              ;; In rust, NODE will be the body of a comment excluding
+              ;; the //, so we need to go to BOL to check for //.
+              (back-to-indentation)
               (looking-at "//"))
             (fill-comment-paragraph arg)
           (c-ts-common--fill-block-comment arg)))