patch 8.2.2558: no error if a lambda argument shadows a variable

Problem:    No error if a lambda argument shadows a variable.
Solution:   Check that the argument name shadows a local, argument or script
            variable. (closes #7898)
diff --git a/src/errors.h b/src/errors.h
index 775c532..db958e0 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -147,7 +147,7 @@
 	INIT(= N_("E1052: Cannot declare an option: %s"));
 EXTERN char e_could_not_import_str[]
 	INIT(= N_("E1053: Could not import \"%s\""));
-EXTERN char e_variable_already_declared_in_script[]
+EXTERN char e_variable_already_declared_in_script_str[]
 	INIT(= N_("E1054: Variable already declared in the script: %s"));
 EXTERN char e_missing_name_after_dots[]
 	INIT(= N_("E1055: Missing name after ..."));
@@ -369,3 +369,7 @@
 	INIT(= N_("E1165: Cannot use a range with an assignment: %s"));
 EXTERN char e_cannot_use_range_with_dictionary[]
 	INIT(= N_("E1166: Cannot use a range with a dictionary"));
+EXTERN char e_argument_name_shadows_existing_variable_str[]
+	INIT(= N_("E1167: Argument name shadows existing variable: %s"));
+EXTERN char e_argument_already_declared_in_script_str[]
+	INIT(= N_("E1168: Argument already declared in the script: %s"));