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/vim9.h b/src/vim9.h
index 440de27..7462b29 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -105,12 +105,12 @@
     ISN_ADDLIST,    // add two lists
     ISN_ADDBLOB,    // add two blobs
 
-    // operation with two arguments; isn_arg.op.op_type is exptype_T
+    // operation with two arguments; isn_arg.op.op_type is exprtype_T
     ISN_OPNR,
     ISN_OPFLOAT,
     ISN_OPANY,
 
-    // comparative operations; isn_arg.op.op_type is exptype_T, op_ic used
+    // comparative operations; isn_arg.op.op_type is exprtype_T, op_ic used
     ISN_COMPAREBOOL,
     ISN_COMPARESPECIAL,
     ISN_COMPARENR,
@@ -217,7 +217,7 @@
 
 // arguments to ISN_OPNR, ISN_OPFLOAT, etc.
 typedef struct {
-    exptype_T	op_type;
+    exprtype_T	op_type;
     int		op_ic;	    // TRUE with '#', FALSE with '?', else MAYBE
 } opexpr_T;