patch 8.2.0044: expression type is used inconsistently

Problem:    Expression type is used inconsistently.
Solution:   Add "ETYPE_IS" and "ETYPE_ISNOT" as separate enum values.  Rename
            "TYPE_" to "ETYPE_" to avoid confusion.
diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index a349723..b086079 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -72,7 +72,7 @@
 void ex_execute(exarg_T *eap);
 char_u *find_option_end(char_u **arg, int *opt_flags);
 void last_set_msg(sctx_T script_ctx);
-int typval_compare(typval_T *typ1, typval_T *typ2, exptype_T type, int type_is, int ic);
+int typval_compare(typval_T *typ1, typval_T *typ2, exptype_T type, int ic);
 char_u *typval_tostring(typval_T *arg);
 char_u *do_string_sub(char_u *str, char_u *pat, char_u *sub, typval_T *expr, char_u *flags);
 /* vim: set ft=c : */