lang/go125: Update to 1.25.13
Changes:
go1.25.13 (released 2026-08-13) includes security fixes to the go command, and the crypto/tls, encoding/asn1, encoding/xml, html/template, net/http, and net/url packages, as well as bug fixes to the compiler, the runtime, and the crypto/tls and os packages.
MFH: 2026Q3
(cherry picked from commit 7f0862a40fff405f30c9becdacf75b8716ff3179)