_content: fix quoting in toolchain.md

Change-Id: I49d34c68bcfc31f2ef7d715fbcf65962c942c8d0
Reviewed-on: https://go-review.googlesource.com/c/website/+/503955
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

_content/doc/toolchain.md

@@ -79,7 +79,7 @@ The language version for a Go version is the result of truncating everything aft
 
 Released Go toolchains such as Go 1.21.0 and Go 1.21rc1 report that specific version
 (for example, `go1.21.0` or `go1.21rc1`)
-from `go version` and [`runtime.Version](/pkg/runtime/#Version).
+from `go version` and [`runtime.Version`](/pkg/runtime/#Version).
 Unreleased (still in development) Go toolchains built from the Go development repository
 instead report only the language version (for example, `go1.21`).