patch 8.1.0176: overlapping string argument for strcpy()

Problem:    Overlapping string argument for strcpy(). (Coverity)
Solution:   Use STRMOVE() instead of STRCPY(). (Dominique Pelle, closes #3187)
diff --git a/src/term.c b/src/term.c
index 21f9a3c..209a03f 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1483,7 +1483,7 @@
 			    if (term_7to8bit(t))
 			    {
 				*t = term_7to8bit(t);
-				STRCPY(t + 1, t + 2);
+				STRMOVE(t + 1, t + 2);
 			    }
 			term_strings[p->bt_entry] = s;
 			set_term_option_alloced(&term_strings[p->bt_entry]);