patch 9.0.0655: passing modifier codes to a shell running in the GUI

Problem:    passing modifier codes to a shell running in the GUI. (Gary
            Johnson)
Solution:   Include modifier codes into the key and drop the modifiers.
diff --git a/src/os_unix.c b/src/os_unix.c
index 20e979c..145f93f 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5106,7 +5106,8 @@
 			    }
 			}
 
-			len = term_replace_bs_del_keycode(ta_buf, ta_len, len);
+			// Remove Vim-specific codes from the input.
+			len = term_replace_keycodes(ta_buf, ta_len, len);
 
 			/*
 			 * For pipes: echo the typed characters.