Release X.Y (202?-??-??)

Commands which take installables on the command line can now read them from the standard input if passed the --stdin flag. This is primarily useful when you have a large amount of paths which exceed the OS arg limit.
The nix-hash command now supports Base64 and SRI. Use the flags --base64 or --sri to specify the format of output hash as Base64 or SRI, and --to-base64 or --to-sri to convert a hash to Base64 or SRI format, respectively.

As the choice of hash formats is no longer binary, the --base16 flag is also added to explicitly specify the Base16 format, which is still the default.
The special handling of an installable with .drv suffix being interpreted as all of the given store derivation's output paths is removed, and instead taken as the literal store path that it represents.

The new ^ syntax for store paths introduced in Nix 2.13 allows explicitly referencing output paths of a derivation. Using this is better and more clear than relying on the now-removed .drv special handling.

For example,
```
$ nix path-info /nix/store/gzaflydcr6sb3567hap9q6srzx8ggdgg-glibc-2.33-78.drv
```
now gives info about the derivation itself, while
```
$ nix path-info /nix/store/gzaflydcr6sb3567hap9q6srzx8ggdgg-glibc-2.33-78.drv^*
```
provides information about each of its outputs.
The experimental command nix describe-stores has been removed.
Nix stores and their settings are now documented in nix help-stores.