relnote: mention a nodemap bug fixes
The fix was in
a3720569a43f.
Differential Revision: https://phab.mercurial-scm.org/D10499
relnote: document the use of persistent-nodemap by default for Rust build
Differential Revision: https://phab.mercurial-scm.org/D10498
relnode: document the move to `zstd` as default compression
Differential Revision: https://phab.mercurial-scm.org/D10497
relnote: clarify the backward compatibility entry about p1/p2 swap
The previous message might read a bit scary. So we clarify that the nodeid are
not affected.
Differential Revision: https://phab.mercurial-scm.org/D10496