Lint - Enable `no-sloppy-imports` even when `--unstable-sloppy-imports` is not specified

[dsherret]

See https://github.com/denoland/deno/issues/28133#issuecomment-2798763180

Also, the help text should reference the lint rule documentation instead of the unstable docs:

error[no-sloppy-imports]: Sloppy imports are not allowed.
  --> ...
   | 
24 | ...

  docs: https://docs.deno.com/runtime/manual/tools/unstable_flags/#--unstable-sloppy-imports

Something to think about: what if people want to allow .js extensions for .ts files for better compatibility with other tooling?

[mintydev789]

Is there anything unstable about this lint rule anymore?