build / doc: missing platform and toolchain info for `linux-x64-musl`

[MikeMcC399]

Situation

Refs: #63737

Alpine Linux has been promoted to Tier 2 support and the BUILDING > Platform list now contains the entry:

Operating System	Architectures	Versions	Support Type	Notes
GNU/Linux	x64	kernel >= 6.12, musl >= 1.2.5	Tier 2	e.g. Alpine 3.22

Binaries now include linux-x64-musl builds on https://nodejs.org/download/release/, for example for Node.js 26.10.0:

node-v26.10.0-linux-x64-musl.tar.gz                22 Sept 2026, 09:01                62 MB
node-v26.10.0-linux-x64-musl.tar.xz                22 Sept 2026, 09:01                34 MB

The BUILDING > Official binary platforms and toolchains however does not provide any information about the Platform and Toolchain used to build the Binary package linux-x64-musl.

Suggestion

Add information to the table BUILDING > Official binary platforms and toolchains for linux-x64-musl.