Add CHANGELOG entry for pcase changes

I'm an Org newb, so hopefully this is well-formatted.

CHANGELOG.org

@@ -11,6 +11,9 @@
   * Add ~lsp-flush-delayed-changes-before-next-message~ customization point to enforce throttling document change notifications.
   * Fix bug in ~rust-analyzer.check.features~ configuration via ~lsp-rust-checkonsave-features~ Emacs setting: we were defaulting to ~[]~, but ~rust-analyzer~ defaults to inheriting the value from ~rust-analyzer.cargo.features~. The bug resulted in code hidden behind features not getting type checked when those features were enabled by setting ~rust-analyzer.cargo.features~ via the ~lsp-rust-features~ Emacs setting.
   * Change ~ruff-lsp~ to ~ruff~ for python lsp client. All ~ruff-lsp~ customizable variable change to ~ruff~. Lsp server command now is ~["ruff" "server"]~ instead of ~["ruff-lsp"]~.
+  * Replace the per-interface ~(INTERFACE ...)~ pcase forms with a single,
+    unified ~(lsp-interface INTERFACE ...)~ form. The per-interface forms are no
+    longer generated. **This is a breaking change.** (See #4430.)
 
 ** 9.0.0
   * Add language server config for QML (Qt Modeling Language) using qmlls.