Rename the master branch to main (#1924)

* This PR is against a branch called `main`
* Internally all docs/CI/etc is updated
* The default branch of the repo is now `main`
* All active PRs have been updated to retarget `main`

Closes #1914

cranelift/codegen/src/result.rs

@@ -21,7 +21,7 @@ pub enum CodegenError {
     /// Cranelift can compile very large and complicated functions, but the [implementation has
     /// limits][limits] that cause compilation to fail when they are exceeded.
     ///
-    /// [limits]: https://github.com/bytecodealliance/wasmtime/blob/master/cranelift/docs/ir.md#implementation-limits
+    /// [limits]: https://github.com/bytecodealliance/wasmtime/blob/main/cranelift/docs/ir.md#implementation-limits
     #[error("Implementation limit exceeded")]
     ImplLimitExceeded,