doc: recommend supported Python versions

Refs: nodejs#50209 (comment)

BUILDING.md

@@ -230,7 +230,7 @@ The Node.js project supports Python >= 3 for building and testing.
 
 * `gcc` and `g++` >= 10.1 or newer
 * GNU Make 3.81 or newer
-* Python >=3.6 <=3.11 (see note above)
+* [A supported version of Python][]
   * For test coverage, your Python installation must include pip.
 
 Installation via Linux package manager can be achieved with:
@@ -246,7 +246,7 @@ FreeBSD and OpenBSD users may also need to install `libexecinfo`.
 #### macOS prerequisites
 
 * Xcode Command Line Tools >= 13 for macOS
-* Python >=3.6 <=3.11 (see note above)
+* [A supported version of Python][]
   * For test coverage, your Python installation must include pip.
 
 macOS users can install the `Xcode Command Line Tools` by running
@@ -887,3 +887,5 @@ incompatible with the official Node.js builds (e.g. using a ABI incompatible
 version of a dependency), please reserve and use a custom `NODE_MODULE_VERSION`
 by opening a pull request against the registry available at
 <https://github.com/nodejs/node/blob/HEAD/doc/abi_version_registry.json>.
+
+[A supported version of Python]: https://devguide.python.org/versions/