patch 8.2.0069: ETYPE_ is used for two different enums

Problem:    ETYPE_ is used for two different enums.
Solution:   Rename one to use EXPR_.
diff --git a/src/structs.h b/src/structs.h
index c995d4b..5f32e1d 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -3662,17 +3662,17 @@
  */
 typedef enum
 {
-    ETYPE_UNKNOWN = 0,
-    ETYPE_EQUAL,	// ==
-    ETYPE_NEQUAL,	// !=
-    ETYPE_GREATER,	// >
-    ETYPE_GEQUAL,	// >=
-    ETYPE_SMALLER,	// <
-    ETYPE_SEQUAL,	// <=
-    ETYPE_MATCH,	// =~
-    ETYPE_NOMATCH,	// !~
-    ETYPE_IS,		// is
-    ETYPE_ISNOT,	// isnot
+    EXPR_UNKNOWN = 0,
+    EXPR_EQUAL,		// ==
+    EXPR_NEQUAL,	// !=
+    EXPR_GREATER,	// >
+    EXPR_GEQUAL,	// >=
+    EXPR_SMALLER,	// <
+    EXPR_SEQUAL,	// <=
+    EXPR_MATCH,		// =~
+    EXPR_NOMATCH,	// !~
+    EXPR_IS,		// is
+    EXPR_ISNOT,		// isnot
 } exptype_T;
 
 /*