Fix some broken links in toolchains.md.
Fix some broken links in toolchains.md.

PiperOrigin-RevId: 312423097

katre/bazel,twitter-forks/bazel,werkt/bazel,bazelbuild/bazel,werkt/bazel,katre/bazel,bazelbuild/bazel,werkt/bazel,davidzchen/bazel,davidzchen/bazel,ButterflyNetwork/bazel,meteorcloudy/bazel,katre/bazel,ulfjack/bazel,bazelbuild/bazel,cushon/bazel,safarmer/bazel,ulfjack/bazel,perezd/bazel,davidzchen/bazel,davidzchen/bazel,perezd/bazel,twitter-forks/bazel,perezd/bazel,safarmer/bazel,twitter-forks/bazel,safarmer/bazel,ulfjack/bazel,bazelbuild/bazel,katre/bazel,meteorcloudy/bazel,perezd/bazel,werkt/bazel,werkt/bazel,davidzchen/bazel,katre/bazel,davidzchen/bazel,twitter-forks/bazel,werkt/bazel,perezd/bazel,twitter-forks/bazel,meteorcloudy/bazel,meteorcloudy/bazel,ButterflyNetwork/bazel,cushon/bazel,perezd/bazel,katre/bazel,bazelbuild/bazel,cushon/bazel,perezd/bazel,safarmer/bazel,davidzchen/bazel,cushon/bazel,cushon/bazel,twitter-forks/bazel,safarmer/bazel,bazelbuild/bazel,ButterflyNetwork/bazel,cushon/bazel,ulfjack/bazel,meteorcloudy/bazel,ButterflyNetwork/bazel,ulfjack/bazel,meteorcloudy/bazel,twitter-forks/bazel,ulfjack/bazel,ButterflyNetwork/bazel,meteorcloudy/bazel,ulfjack/bazel,ButterflyNetwork/bazel,safarmer/bazel