Fix MCP links

src/contributing.md

@@ -81,7 +81,7 @@ smaller user-facing changes.
 into a PR that ends up not getting merged!** [See this document][mcpinfo] for
 more info on MCPs.
 
-[mcpinfo]: https://forge.rust-lang.org/compiler/mcp.html
+[mcpinfo]: https://forge.rust-lang.org/compiler/proposals-and-stabilization.html#how-do-i-submit-an-mcp
 [zulip]: https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler
 
 ### Performance

src/implementing_new_features.md

@@ -44,7 +44,7 @@ like this; for example, the compiler team recommends
 filing a Major Change Proposal ([MCP][mcp]) as a lightweight way to
 garner support and feedback without requiring full consensus.
 
-[mcp]: https://forge.rust-lang.org/compiler/mcp.html#public-facing-changes-require-rfcbot-fcp
+[mcp]: https://forge.rust-lang.org/compiler/proposals-and-stabilization.html#how-do-i-submit-an-mcp
 
 You don't need to have the implementation fully ready for r+ to propose an FCP,
 but it is generally a good idea to have at least a proof