Add URL to test cases

tests/rustdoc-ui/issues/issue-101076.rs

@@ -1,4 +1,5 @@
 //@ check-pass
+// https://github.com/rust-lang/rust/issues/101076
 
 const _: () = {
     #[macro_export]

tests/rustdoc-ui/issues/issue-102986.rs

@@ -1,3 +1,4 @@
+// https://github.com/rust-lang/rust/issues/102986
 struct Struct {
     y: (typeof("hey"),),
     //~^ `typeof` is a reserved keyword but unimplemented

tests/rustdoc-ui/issues/issue-103997.rs

@@ -1,4 +1,5 @@
 //@ check-pass
+// https://github.com/rust-lang/rust/issues/103997
 
 pub fn foo() {}
 

tests/rustdoc-ui/issues/issue-105334.rs

@@ -1,2 +1,3 @@
+// https://github.com/rust-lang/rust/issues/105334
 impl Vec< br##"*.."## > {}
 //~^ ERROR

tests/rustdoc-ui/issues/issue-105737.rs

@@ -1,3 +1,4 @@
+// https://github.com/rust-lang/rust/issues/105737
 impl Vec<lol> {}
 //~^ ERROR
 

tests/rustdoc-ui/issues/issue-105742.rs

@@ -1,4 +1,5 @@
 //@ compile-flags: -Znormalize-docs
+// https://github.com/rust-lang/rust/issues/105742
 use std::ops::Index;
 
 pub fn next<'a, T>(s: &'a mut dyn SVec<Item = T, Output = T>) {

tests/rustdoc-ui/issues/issue-106213.rs

@@ -1,5 +1,6 @@
 //@ compile-flags: --document-private-items
 //@ edition:2021
+// https://github.com/rust-lang/rust/issues/106213
 
 fn use_avx() -> dyn  {
     //~^ ERROR at least one trait is required for an object type

tests/rustdoc-ui/issues/issue-107918.rs

@@ -2,6 +2,7 @@
 //@ compile-flags: --document-private-items
 //@ build-pass
 //@ only-linux
+// https://github.com/rust-lang/rust/issues/107918
 
 #![no_std]
 #![no_main]

tests/rustdoc-ui/issues/issue-110900.rs

@@ -1,4 +1,5 @@
 //@ check-pass
+// https://github.com/rust-lang/rust/issues/110900
 
 #![crate_type="lib"]