vim-patch:9.0.0904: various comment and indent flaws (#23498)

Problem:    Various comment and indent flaws.
Solution:   Improve comments and indenting.

88456cd3c4

Omit test_function_lists.vim change as that file is likely not
applicable to Nvim due to the existence of Nvim-only functions.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/eval/window.c

@@ -98,6 +98,7 @@ win_T *win_id2wp(int id)
 }
 
 /// Return the window and tab pointer of window "id".
+/// Returns NULL when not found.
 win_T *win_id2wp_tp(int id, tabpage_T **tpp)
 {
   FOR_ALL_TAB_WINDOWS(tp, wp) {