Update changelog link for Razor bump

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: davidwengier

CHANGELOG.md

@@ -4,7 +4,7 @@
 - Debug from .csproj and .sln [#5876](https://github.com/dotnet/vscode-csharp/issues/5876)
 
 # 2.135.x
-* Update Razor to 10.0.0-preview.26208.5 (PR: [#](https://github.com/dotnet/vscode-csharp/pull/))
+* Update Razor to 10.0.0-preview.26208.5 (PR: [#9162](https://github.com/dotnet/vscode-csharp/pull/9162))
   * Clean up RewrittenSyntaxTree naming and null handling in DefaultTagHelperResolutionPhase (PR: [#13003](https://github.com/dotnet/razor/pull/13003))
   * Deferred tag helper lowering: separate resolution from lowering phase (PR: [#12957](https://github.com/dotnet/razor/pull/12957))
   * Consolidate Edit services, and our two "Generate Method" systems (PR: [#12982](https://github.com/dotnet/razor/pull/12982))