Merge #11726: Cleanups + nit fixes for walletdir PR
aac6b3f067 Update files.md for new wallets/ subdirectory (MeshCollider)
b67342906c Cleanups for walletdir PR (MeshCollider)
Pull request description:
This addresses the remaining nits from https://github.com/bitcoin/bitcoin/pull/11466
- Updates `doc/files.md` with respect to the new default wallet directory
- Fixes @promag and @laanwj's error message nit, and Jonas' release notes nit
- ~Addresses @laanwj's net-specific wallet subdirectory concern in the case that a walletdir is specified~
- Changes the #includes from "" to <> style after #11651
Tree-SHA512: b86bf5fdc4de54c1b0f65b60a83af3cf82b35d216ce9c0de724803bfba6934796238b6c412659dcc29ae2e3e856d4eb97ae777c80f36f4089d8acecfddefe9aa