docs(triple): drop a sentence the table had outgrown

Self-review: the paragraph above the M-profile rows still said "two rows are
verified", written when two were. Four boot under QEMU and the block directly
below already names all four, so the sentence contradicted the table two lines
under it — the kind of stale count a reader trusts because it reads like a
summary.

Author: speak-agent

modules/toolchain-model/src/triple.cppm

@@ -381,9 +381,6 @@ inline constexpr TargetInfo kKnownTargets[] = {
     // package is compiled with the consuming target's own flags, so the ABI
     // agreement holds by construction and there is no multilib at all.
     //
-    // Two rows are `verified` because two have a board and an emulator that
-    // runs them; the rest build and are `preview`, the same standard applied to
-    // `aarch64-none-elf` and `x86_64-none-elf` when they landed.
     // ⚠️ THE TIER COLUMN RECORDS WHAT WAS RUN, NOT WHAT WAS REASONED. Measured
     // 2026-09-04 under `xim:qemu-arm@9.2.4-1`: each `verified` row below built
     // an image that BOOTED on the named machine and printed over semihosting —