Add ui test for #99625

Author: obeis

src/test/ui/parser/issue-99625-enum-struct-mutually-exclusive.fixed

@@ -0,0 +1,13 @@
+// run-rustfix
+
+pub enum Range {
+    //~^ ERROR `enum` and `struct` are mutually exclusive
+    Valid {
+        begin: u32,
+        len: u32,
+    },
+    Out,
+}
+
+fn main() {
+}

src/test/ui/parser/issue-99625-enum-struct-mutually-exclusive.rs

@@ -0,0 +1,13 @@
+// run-rustfix
+
+pub enum struct Range {
+    //~^ ERROR `enum` and `struct` are mutually exclusive
+    Valid {
+        begin: u32,
+        len: u32,
+    },
+    Out,
+}
+
+fn main() {
+}

src/test/ui/parser/issue-99625-enum-struct-mutually-exclusive.stderr

@@ -0,0 +1,8 @@
+error: `enum` and `struct` are mutually exclusive
+  --> $DIR/issue-99625-enum-struct-mutually-exclusive.rs:3:5
+   |
+LL | pub enum struct Range {
+   |     ^^^^^^^^^^^ help: replace `enum struct` with: `enum`
+
+error: aborting due to previous error
+