*: Partial string handling refactoring

Main points:

- Replace `char_u` with `char` in some cases.
- Remove `str[len] = NUL` hack in some cases when `str` may be considered
  `const`.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/nvim/option.c b/src/nvim/option.c
index a218323dac..b1cbe3fb59 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -2569,8 +2569,7 @@ did_set_string_option (
 
       init_highlight(FALSE, FALSE);
 
-      if (dark != (*p_bg == 'd')
-          && get_var_value((char_u *)"g:colors_name") != NULL) {
+      if (dark != (*p_bg == 'd') && get_var_value("g:colors_name") != NULL) {
         /* The color scheme must have set 'background' back to another
          * value, that's not what we want here.  Disable the color
          * scheme and set the colors again. */
@@ -3886,7 +3885,7 @@ set_bool_option (
             "W17: Arabic requires UTF-8, do ':set encoding=utf-8'");
 
         msg_source(hl_attr(HLF_W));
-        MSG_ATTR(_(w_arabic), hl_attr(HLF_W));
+        msg_attr(_(w_arabic), hl_attr(HLF_W));
         set_vim_var_string(VV_WARNINGMSG, _(w_arabic), -1);
       }