Stabilize addition of Python versions to the Windows registry (#14625)

Following #14614 this is non-fatal and has an opt-out so it should be
safe to stabilize.

crates/uv/src/commands/python/install.rs

@@ -501,7 +501,7 @@ pub(crate) async fn install(
             );
         }
 
-        if preview.is_enabled() && !matches!(registry, Some(false)) {
+        if !matches!(registry, Some(false)) {
             #[cfg(windows)]
             {
                 match uv_python::windows_registry::create_registry_entry(installation) {

crates/uv/src/commands/python/uninstall.rs

@@ -211,7 +211,7 @@ async fn do_uninstall(
     }
 
     #[cfg(windows)]
-    if preview.is_enabled() {
+    {
         uv_python::windows_registry::remove_registry_entry(
             &matching_installations,
             all,

docs/concepts/python-versions.md

@@ -435,3 +435,18 @@ are not yet available for musl Linux on ARM).
 ### PyPy distributions
 
 PyPy distributions are provided by the PyPy project.
+
+## Registration in the Windows registry
+
+On Windows, installation of managed Python versions will register them with the Windows registry as
+defined by [PEP 514](https://peps.python.org/pep-0514/).
+
+After installation, the Python versions can be selected with the `py` launcher, e.g.:
+
+```console
+$ uv python install 3.13.1
+$ py -V:Astral/CPython3.13.1
+```
+
+On uninstall, uv will remove the registry entry for the target version as well as any broken
+registry entries.