Fix invalid link

Author: tiif

Diff for: compiler/rustc_middle/src/ty/mod.rs

@@ -953,7 +953,7 @@ impl<'tcx> rustc_type_ir::Flags for Clauses<'tcx> {
 /// environment. `ParamEnv` is the type that represents this information. See the
 /// [dev guide chapter][param_env_guide] for more information.
 ///
-/// [param_env_guide]: https://rustc-dev-guide.rust-lang.org/param_env/param_env_summary.html
+/// [param_env_guide]: https://rustc-dev-guide.rust-lang.org/typing_parameter_envs.html
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 #[derive(HashStable, TypeVisitable, TypeFoldable)]
 pub struct ParamEnv<'tcx> {
@@ -977,7 +977,7 @@ impl<'tcx> ParamEnv<'tcx> {
     /// to use an empty environment. See the [dev guide section][param_env_guide]
     /// for information on what a `ParamEnv` is and how to acquire one.
     ///
-    /// [param_env_guide]: https://rustc-dev-guide.rust-lang.org/param_env/param_env_summary.html
+    /// [param_env_guide]: https://rustc-dev-guide.rust-lang.org/typing_parameter_envs.html
     #[inline]
     pub fn empty() -> Self {
         Self::new(ListWithCachedTypeInfo::empty())