Fix some cases of incomplete code's indentation [c/c++-ts-mode]

* lisp/progmodes/c-ts-mode.el (c-ts-base--before-indent): Try to
guess when the parse tree is incomplete, and provide a better node
to indent against (bug#62717).
(c-ts-base-mode): Set up advice for local treesit-indent-function.

1 files changed, 14 insertions, 0 deletions

diff --git a/test/lisp/progmodes/c-ts-mode-resources/indent.erts b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
index 5cdefe2122c..221b3d809af 100644
--- a/test/lisp/progmodes/c-ts-mode-resources/indent.erts
+++ b/test/lisp/progmodes/c-ts-mode-resources/indent.erts
@@ -464,3 +464,17 @@ main (void)
   |
 }
 =-=-=
+
+Name: Empty Line (Block Start)
+
+=-=
+int
+main (void)
+{
+|
+=-=
+int
+main (void)
+{
+  |
+=-=-=