doc/build.rst: quick pass to fix/update the info

In particular, don't mention things that probably don't work (well):
Windows, amalgamation, very old OpenSUSE package.
6 jobs from doc-packaging-update in 3 minutes and 37 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
canceled #72824
docker linux amd64
build:linux:amd64

00:03:14

passed #16790
docker linux amd64
build:linux:amd64

00:00:34

 
  Test
canceled #73100
docker linux amd64
deckard:linux:amd64

canceled #16793
docker linux amd64 allowed to fail
respdiff:linux:amd64

00:00:09

passed #16791
docker linux amd64
test:linux:amd64

00:00:23

passed #16792
docker linux amd64
deckard:linux:amd64

00:00:33