patch 8.2.2319: "exptype_T" can be read as "expected type"

Problem:    "exptype_T" can be read as "expected type".
Solution:   Rename to "exprtype_T", expression type.
diff --git a/src/eval.c b/src/eval.c
index 5ebe037..9c91e52 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2655,7 +2655,7 @@
 {
     char_u	*p;
     int		getnext;
-    exptype_T	type = EXPR_UNKNOWN;
+    exprtype_T	type = EXPR_UNKNOWN;
     int		len = 2;
     int		type_is = FALSE;