Simplify transition "unsupported --config" documentation.
Simplify transition "unsupported --config" documentation.

- Remove a few details that aren't crucial for first-pass user documentation (like the technical reasons why configurations can't access `--config`).
- Space out the formatting a bit.
- Fix a broken anchor link.

PiperOrigin-RevId: 383699801

katre/bazel,katre/bazel,cushon/bazel,perezd/bazel,cushon/bazel,katre/bazel,perezd/bazel,cushon/bazel,bazelbuild/bazel,perezd/bazel,perezd/bazel,bazelbuild/bazel,perezd/bazel,ButterflyNetwork/bazel,katre/bazel,ButterflyNetwork/bazel,bazelbuild/bazel,bazelbuild/bazel,katre/bazel,katre/bazel,bazelbuild/bazel,bazelbuild/bazel,cushon/bazel,cushon/bazel,ButterflyNetwork/bazel,perezd/bazel,ButterflyNetwork/bazel,cushon/bazel,ButterflyNetwork/bazel,ButterflyNetwork/bazel,perezd/bazel