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/typval.c b/src/typval.c
index d16f0e6..e620bed 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -649,7 +649,7 @@
 typval_compare(
     typval_T	*typ1,   // first operand
     typval_T	*typ2,   // second operand
-    exptype_T	type,    // operator
+    exprtype_T	type,    // operator
     int		ic)      // ignore case
 {
     int		i;