patch 8.2.0344: ":def" not skipped properly

Problem:    ":def" not skipped properly.
Solution:   Add CMD_def to list of commands the require evaluation even when
            not being executed.
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 62cab6e..f2fb646 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -2357,6 +2357,7 @@
 	    case CMD_finally:
 	    case CMD_endtry:
 	    case CMD_function:
+	    case CMD_def:
 				break;
 
 	    // Commands that handle '|' themselves.  Check: A command should