Add test for #![doc(test(...)] with literal parameter

tests/ui/attributes/doc-test-literal.rs

@@ -0,0 +1,7 @@
+#![deny(warnings)]
+
+#![doc(test(""))]
+//~^ ERROR `#![doc(test(...)]` does not take a literal
+//~^^ WARN this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+
+fn main() {}

tests/ui/attributes/doc-test-literal.stderr

@@ -0,0 +1,17 @@
+error: `#![doc(test(...)]` does not take a literal
+  --> $DIR/doc-test-literal.rs:3:13
+   |
+LL | #![doc(test(""))]
+   |             ^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #82730 <https://github.com/rust-lang/rust/issues/82730>
+note: the lint level is defined here
+  --> $DIR/doc-test-literal.rs:1:9
+   |
+LL | #![deny(warnings)]
+   |         ^^^^^^^^
+   = note: `#[deny(invalid_doc_attributes)]` implied by `#[deny(warnings)]`
+
+error: aborting due to previous error
+