Add test for enum variant value display

Author: GuillaumeGomez

tests/rustdoc/enum-variant-value.rs

@@ -0,0 +1,15 @@
+// This test ensures that the variant value is displayed with underscores but without
+// a type name at the end.
+
+#![crate_name = "foo"]
+
+// @has 'foo/enum.B.html'
+// @has - '//*[@class="rust item-decl"]/code' 'A = 12,'
+// @has - '//*[@class="rust item-decl"]/code' 'C = 1_245,'
+// @matches - '//*[@id="variant.A"]/h3' '^A = 12$'
+// @matches - '//*[@id="variant.C"]/h3' '^C = 1_245$'
+pub enum B {
+    A = 12,
+    B,
+    C = 1245,
+}