document Rust 1.90 changes

Author: tshepang

src/changelog.rst

@@ -18,6 +18,21 @@ with the change that has been applied due to it.
    just the language changes that had an impact to the FLS. See the `release
    notes`_ for a full list of changes.
 
+Language changes in Rust 1.90.0
+-------------------------------
+
+- `Split up the unknown_or_malformed_diagnostic_attributes lint <https://github.com/rust-lang/rust/pull/140717>`_
+
+  - No change: lints are not part of the FLS
+
+- `Allow constants whose final value has references to mutable/external memory, but reject such constants as patterns <https://github.com/rust-lang/rust/pull/140942>`_
+
+  - New paragraph: :p:`fls_wJ9f906BlBvg`
+
+- `Allow volatile access to non-Rust memory, including address 0 <https://github.com/rust-lang/rust/pull/141260>`_
+
+  - No change: lints are not part of the FLS
+
 Language changes in Rust 1.89.0
 -------------------------------
 

src/patterns.rst

@@ -370,6 +370,12 @@ When a :t:`path pattern` refers to an :t:`associated constant` or a
 :t:`constant`, the :t:`type` of the :t:`associated constant` or :t:`constant`
 shall be :t:`structurally equal`.
 
+:dp:`fls_wJ9f906BlBvg`
+When a :t:`path pattern` refers to an :t:`associated constant` or a
+:t:`constant`, the :t:`constant` must not contain any references to
+:t:`[mutable static]s`, :t:`[static]s` with :t:`interior mutability`,
+or :t:`[external static]s`.
+
 :dp:`fls_hF19K8sWU8FF`
 When the type of the :t:`path pattern` is of an :t:`enum type` or
 :t:`struct type`, then the :t:`enum type` or :t:`struct type` shall be subject