patch 9.0.0489: using "end_lnum" with virtual text causes problems

Problem:    Using "end_lnum" with virtual text causes problems.
Solution:   Disallow using "end_lnum" with virtual text. (closes #11151)
            Also disallow "end_col" and "length".
diff --git a/src/errors.h b/src/errors.h
index 5f0fdcb..944dc43 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3338,3 +3338,7 @@
 EXTERN char e_cannot_use_type_with_this_variable_str[]
 	INIT(= N_("E1304: Cannot use type with this variable: %s"));
 #endif
+#ifdef FEAT_PROP_POPUP
+EXTERN char e_cannot_use_length_endcol_and_endlnum_with_text[]
+	INIT(= N_("E1305: Cannot use \"length\", \"end_col\" and \"end_lnum\" with \"text\""));
+#endif