doc: clarify supported Python releases

Exclude Python pre-release versions

Signed-off-by: Mike McCready <66998419+MikeMcC399@users.noreply.github.com>
PR-URL: #65850
Fixes: #65599
Refs: #65750
Reviewed-By: Richard Lau <richard.lau@ibm.com>
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>

Author: MikeMcC399

BUILDING.md

@@ -241,7 +241,7 @@ tarball and/or browse the git repository checked out at the relevant tag.
 
 ### Prerequisites
 
-* [A supported version of Python][Python versions] for building and testing.
+* [A supported version of Python][Python versions] (excludes pre-release versions) for building and testing.
 * A Rust toolchain if [building Node.js with Temporal support](#building-nodejs-with-temporal-support).
 * Memory: at least 8GB of RAM is typically required when compiling with 4 parallel jobs (e.g: `make -j4`).