feat(ui): add 'statuscolumn' option

Problem:    Unable to customize the column next to a window ('gutter').
Solution:   Add 'statuscolumn' option that follows the 'statusline' syntax,
	    allowing to customize the status column. Also supporting the %@
	    click execute function label. Adds new items @C and @s which
	    will print the fold and sign columns. Line numbers and signs
	    can be clicked, highlighted, aligned, transformed, margined etc.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 52ab2ad25e..afdb04ebd8 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -780,6 +780,16 @@ int number_width(win_T *wp)
   }
   wp->w_nrwidth_line_count = lnum;
 
+  // make best estimate for 'statuscolumn'
+  if (*wp->w_p_stc != NUL) {
+    char buf[MAXPATHL];
+    wp->w_nrwidth_width = 0;
+    n = build_statuscol_str(wp, true, false, lnum, 0, 0, NUL, buf, NULL, NULL);
+    n = MAX(n, (wp->w_p_nu || wp->w_p_rnu) * (int)wp->w_p_nuw);
+    wp->w_nrwidth_width = MIN(n, MAX_NUMBERWIDTH);
+    return wp->w_nrwidth_width;
+  }
+
   n = 0;
   do {
     lnum /= 10;