feat(api): evaluate 'statuscolumn' with nvim_eval_statusline()

runtime/doc/api.txt

@@ -773,6 +773,8 @@ nvim_eval_statusline({str}, {*opts})                  *nvim_eval_statusline()*
                 • use_tabline: (boolean) Evaluate tabline instead of
                   statusline. When true, {winid} is ignored. Mutually
                   exclusive with {use_winbar}.
+                • use_statuscol: (boolean) Evaluate statuscolumn instead of
+                  statusline.
 
     Return: ~
         Dictionary containing statusline information, with these keys:

runtime/doc/news.txt

@@ -73,6 +73,9 @@ NEW FEATURES                                                    *news-features*
 
 The following new APIs or features were added.
 
+• |nvim_eval_statusline()| supports evaluating the |'statuscolumn'| through a
+  new `opts` field: `use_statuscol`.
+
 • |nvim_buf_get_extmarks()| now accepts a -1 `ns_id` to request extmarks from
   all namespaces and adds the namespace id to the details array.
   Other missing properties have been added to the details array and marks can