Merge bitcoin/bitcoin#28884: doc: remove x86_64 build assumption from depends doc

821a8a1 doc: remove x86_64 build assumption from depends doc (fanquake)

Pull request description:

  This dates from the introduction of depends, and has not been the case for some time now.

ACKs for top commit:
  maflcko:
    lgtm ACK 821a8a1
  hebasto:
    ACK 821a8a1.
  theuni:
    ACK 821a8a1

Tree-SHA512: 640967a3e6dfab495fd733d3379aa916ac7f67e89a92ef6a94c3bea0494dc7921a9d7485e1b90a1beab00548b575cdab8fb08eb9267dcc5e890cc796ae1b6875

Author: fanquake

depends/description.md

@@ -6,8 +6,7 @@ There are several features that make it different from most similar systems:
 In theory, binaries for any target OS/architecture can be created, from a
 builder running any OS/architecture. In practice, build-side tools must be
 specified when the defaults don't fit, and packages must be amended to work
-on new hosts. For now, a build architecture of x86_64 is assumed, either on
-Linux or macOS.
+on new hosts.
 
 ### No reliance on timestamps