docs: misc (#29622)

Co-authored-by: Christian Clason <c.clason@uni-graz.at>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>

src/nvim/getchar.c

@@ -1678,8 +1678,8 @@ int vgetc(void)
         vgetc_char = c;
       }
 
-      // a keypad or special function key was not mapped, use it like
-      // its ASCII equivalent
+      // A keypad or special function key was not mapped, use it like
+      // its ASCII equivalent.
       switch (c) {
       case K_KPLUS:
         c = '+'; break;