patch 8.2.3787: no proper formatting of a C line comment after a statement

Problem:    No proper formatting of a C line comment after a statement.
Solution:   Find the start of the line comment, insert the comment leader and
            indent the comment properly.
diff --git a/src/edit.c b/src/edit.c
index 8dd6094..40d5c4e 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -5147,7 +5147,8 @@
 
     AppendToRedobuff(NL_STR);
     i = open_line(FORWARD,
-	    has_format_option(FO_RET_COMS) ? OPENLINE_DO_COM : 0, old_indent);
+	    has_format_option(FO_RET_COMS) ? OPENLINE_DO_COM : 0, old_indent,
+	    NULL);
     old_indent = 0;
 #ifdef FEAT_CINDENT
     can_cindent = TRUE;