[ty] Improve documentation for extra-paths and python config settings (#20717)

Co-authored-by: Micha Reiser <micha@reiser.io>

crates/ty/docs/cli.md

@@ -54,7 +54,8 @@ over all configuration files.</p>
 </dd><dt id="ty-check--exclude"><a href="#ty-check--exclude"><code>--exclude</code></a> <i>exclude</i></dt><dd><p>Glob patterns for files to exclude from type checking.</p>
 <p>Uses gitignore-style syntax to exclude files and directories from type checking. Supports patterns like <code>tests/</code>, <code>*.tmp</code>, <code>**/__pycache__/**</code>.</p>
 </dd><dt id="ty-check--exit-zero"><a href="#ty-check--exit-zero"><code>--exit-zero</code></a></dt><dd><p>Always use exit code 0, even when there are error-level diagnostics</p>
-</dd><dt id="ty-check--extra-search-path"><a href="#ty-check--extra-search-path"><code>--extra-search-path</code></a> <i>path</i></dt><dd><p>Additional path to use as a module-resolution source (can be passed multiple times)</p>
+</dd><dt id="ty-check--extra-search-path"><a href="#ty-check--extra-search-path"><code>--extra-search-path</code></a> <i>path</i></dt><dd><p>Additional path to use as a module-resolution source (can be passed multiple times).</p>
+<p>This is an advanced option that should usually only be used for first-party or third-party modules that are not installed into your Python environment in a conventional way. Use <code>--python</code> to point ty to your Python environment if it is in an unusual location.</p>
 </dd><dt id="ty-check--help"><a href="#ty-check--help"><code>--help</code></a>, <code>-h</code></dt><dd><p>Print help (see a summary with '-h')</p>
 </dd><dt id="ty-check--ignore"><a href="#ty-check--ignore"><code>--ignore</code></a> <i>rule</i></dt><dd><p>Disables the rule. Can be specified multiple times.</p>
 </dd><dt id="ty-check--output-format"><a href="#ty-check--output-format"><code>--output-format</code></a> <i>output-format</i></dt><dd><p>The format to use for printing diagnostic messages</p>
@@ -67,11 +68,10 @@ over all configuration files.</p>
 </ul></dd><dt id="ty-check--project"><a href="#ty-check--project"><code>--project</code></a> <i>project</i></dt><dd><p>Run the command within the given project directory.</p>
 <p>All <code>pyproject.toml</code> files will be discovered by walking up the directory tree from the given project directory, as will the project's virtual environment (<code>.venv</code>) unless the <code>venv-path</code> option is set.</p>
 <p>Other command-line arguments (such as relative paths) will be resolved relative to the current working directory.</p>
-</dd><dt id="ty-check--python"><a href="#ty-check--python"><code>--python</code></a>, <code>--venv</code> <i>path</i></dt><dd><p>Path to the Python environment.</p>
-<p>ty uses the Python environment to resolve type information and third-party dependencies.</p>
-<p>If not specified, ty will attempt to infer it from the <code>VIRTUAL_ENV</code> or <code>CONDA_PREFIX</code> environment variables, or discover a <code>.venv</code> directory in the project root or working directory.</p>
-<p>If a path to a Python interpreter is provided, e.g., <code>.venv/bin/python3</code>, ty will attempt to find an environment two directories up from the interpreter's path, e.g., <code>.venv</code>. At this time, ty does not invoke the interpreter to determine the location of the environment. This means that ty will not resolve dynamic executables such as a shim.</p>
-<p>ty will search in the resolved environment's <code>site-packages</code> directories for type information and third-party imports.</p>
+</dd><dt id="ty-check--python"><a href="#ty-check--python"><code>--python</code></a>, <code>--venv</code> <i>path</i></dt><dd><p>Path to your project's Python environment or interpreter.</p>
+<p>ty uses your Python environment to resolve third-party imports in your code.</p>
+<p>If you're using a project management tool such as uv or you have an activated Conda or virtual environment, you should not generally need to specify this option.</p>
+<p>This option can be used to point to virtual or system Python environments.</p>
 </dd><dt id="ty-check--python-platform"><a href="#ty-check--python-platform"><code>--python-platform</code></a>, <code>--platform</code> <i>platform</i></dt><dd><p>Target platform to assume when resolving types.</p>
 <p>This is used to specialize the type of <code>sys.platform</code> and will affect the visibility of platform-specific functions and attributes. If the value is set to <code>all</code>, no assumptions are made about the target platform. If unspecified, the current system's platform will be used.</p>
 </dd><dt id="ty-check--python-version"><a href="#ty-check--python-version"><code>--python-version</code></a>, <code>--target-version</code> <i>version</i></dt><dd><p>Python version to assume when resolving types.</p>