patch 8.2.1288: Vim9: cannot use mark in range

Problem:    Vim9: cannot use mark in range.
Solution:   Use the flag that a colon was seen. (closes #6528)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 85747d5..5459cfd 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -1773,7 +1773,7 @@
  */
     cmd = ea.cmd;
 #ifdef FEAT_EVAL
-    starts_with_quote = vim9script && *ea.cmd == '\'';
+    starts_with_quote = vim9script && !starts_with_colon && *ea.cmd == '\'';
     if (!starts_with_quote)
 #endif
 	ea.cmd = skip_range(ea.cmd, NULL);