Rollup merge of #146788 - sysrex:146756/discord_invite, r=workingjubilee

chore: removes deprecated discord.

This PR just changes the wording of the contributing document to remove the deprecated Discord.

Fixes #146756.

Author: matthiaskrgr

CONTRIBUTING.md

@@ -31,8 +31,8 @@ bootstrapping, the compiler architecture, source code representation, and more.
 
 ## [Getting help](https://rustc-dev-guide.rust-lang.org/getting-started.html#asking-questions)
 
-There are many ways you can get help when you're stuck. Rust has many platforms for this:
-[internals], [rust-zulip], and [rust-discord]. It is recommended to ask for help on
+There are many ways you can get help when you're stuck. Rust has two platforms for this:
+[internals] and [rust-zulip]. It is recommended to ask for help on
 the [rust-zulip], but any of these platforms are great ways to seek help and even
 find a mentor! You can learn more about asking questions and getting help in the
 [Asking Questions](https://rustc-dev-guide.rust-lang.org/getting-started.html#asking-questions) chapter of the [rustc-dev-guide].