Remove duplicate sentences in `env` attribute documentation
</p>
<p>
- This attribute only applies to native rules, like <code>cc_test</code>, <code>py_test</code>,
- and <code>sh_test</code>. It does not apply to Starlark-defined test rules.
This attribute only applies to native rules, like <code>cc_test</code>,
<code>py_test</code>, and <code>sh_test</code>. It does not apply to
Starlark-defined test rules. For your own Starlark rules, you can add an "env"
