fix the Discord links with the new #nufmt channel

docs/CONTRIBUTING.md

@@ -4,7 +4,7 @@ Salutations! Thanks for coming by and the interest into this project!
 We would like to order the contributions like this:
 
 - Before you start hacking, it is important to **ask first** if your idea or bugfix is in order.
-Create an issue or come and say hi in the [`#nufmt` channel](https://discord.com/channels/601130461678272522/1087437882396004442) by joining [the discord](https://discord.gg/NtAbbGn).
+Create an issue or come and say hi in the [`#nufmt` channel][nufmt discord channel] by joining [the discord][Nushell discord].
 We don't bite!.
 
  It would be sad that you do the effort to clone the project, successfully make the PR, but it wasn't in our plans or there is another PR that is currently adressing that issue.
@@ -18,3 +18,6 @@ This is a list of things we would like to have and mantain across time. Please d
 
 - Everything should be explained: rust docs, comments, drawings, pick what makes you comfortable, but it is important to make it clear. There will always be some new guy or gal into the project we want to welcome 😄.
 - Use clear variable names and try to avoid confusing abbreviations. Think that your peers may not be fully fluent in english 💬.
+
+[Nushell discord]: https://discord.gg/NtAbbGn
+[nufmt discord channel]: https://discord.com/channels/601130461678272522/1117921521520873623