Fix links in the contributing docs

CONTRIBUTING.md

@@ -4,30 +4,44 @@ Thank you for your interest in contributing to Koto!
 
 ## Reporting bugs
 
-Please feel free to [open an issue](https://github.com/koto-lang/koto/issues/new) if you find a problem in Koto.
+Please feel free to [open an issue][new-issue] if you find a problem in Koto.
 
 ## Improving the docs
 
-As Koto is a new language with a goal of being easy to learn, one of the most important contributions you can make is to read the [language guide](https::/koto.dev/docs/next/language) and [core library reference](https::/koto.dev/docs/next/core_lib). If you find something confusing or incomplete, then its likely that others will to, and your suggestions for improvements will be invaluable.
+As Koto is a new language with a goal of being easy to learn, one of the most important contributions you can make is to read the [language guide][guide] and [core library reference][core-lib]. If you find something confusing or incomplete, then its likely that others will to, and your suggestions for improvements will be invaluable.
 
-The documentation is maintained in [this repo](./crates/cli/docs). To see how changes to the documentation look on the website, take a look at the [website's contributing guide](https://github.com/koto-lang/koto.dev/tree/main/CONTRIBUTING.md).
+The documentation is maintained in [this repo][docs]. To see how changes to the documentation look on the website, take a look at the [website's contributing guide][website-contributing].
 
 ## Working on issues
 
-Please feel to take a look at the [open issues](https://github.com/koto-lang/koto/issues/) to see if there's something you'd like to work on. If you don't see anything that fits your interests then you're welcome to ask on [Discord](https://discord.gg/JeV8RuK4CT).
+Please feel to take a look at the [open issues][open-issues] to see if there's something you'd like to work on. If you don't see anything that fits your interests then you're welcome to ask on [Discord][discord].
 
 ## Adding new libraries
 
-The [`libs`](./libs/) directory includes several non-core libraries for Koto, and until Koto has a package management system, more could be added as long as they don't pull in large dependencies.
+The [`libs`][libs] directory includes several non-core libraries for Koto, and until Koto has a package management system, more could be added as long as they don't pull in large dependencies.
 
 If you would like to add a new library, please make a proposal first in a new issue or discussion.
 
-Libraries should include documentation for all new Koto functions in the [lib docs directory](./crates/cli/docs/libs/).
+Libraries should include documentation for all new Koto functions in the [lib docs directory][lib-docs].
 
 ## Improving the website
 
-The [Koto website](https::koto.dev) is in [this repo](https://github.com/koto-lang/koto.dev), please refer to [its contributing guide](https://github.com/koto-lang/koto.dev/CONTRIBUTING.md).
+The [Koto website][website] is in [this repo][website-repo], please refer to [its contributing guide][website-contributing].
 
 ## Improving performance
 
-- Performance improvements for Koto are always welcome. There are a collection of benchmarks in the [koto/benches](./koto/benches/) folder which can be run via `cargo bench`. The benchmarks aren't comprehensive, contributions are welcome! The benchmarks are configured in [crates/koto/benches](./crates/koto/benches/koto_benchmark.rs).
+- Performance improvements for Koto are always welcome. There are a collection of benchmarks in the [koto/benches][benches] folder which can be run via `cargo bench`. The benchmarks aren't comprehensive, contributions are welcome! The benchmarks are configured in [crates/koto/benches][benches-runner].
+
+[benches]: ./koto/benches/
+[benches-runner]: ./crates/koto/benches/koto_benchmark.rs
+[core-lib]: https://koto.dev/docs/next/core_lib
+[discord]: https://discord.gg/JeV8RuK4CT
+[docs]: ./crates/cli/docs
+[libs]: ./libs/
+[lib-docs]: ./crates/cli/docs/libs/
+[new-issue]: https://github.com/koto-lang/koto/issues/new
+[open-issues]: https://github.com/koto-lang/koto/issues/
+[guide]: https://koto.dev/docs/next/language
+[website]: https://koto.dev
+[website-contributing]: https://github.com/koto-lang/koto.dev/tree/main/CONTRIBUTING.md
+[website-repo]: https://github.com/koto-lang/koto.dev