nix: include commit hash in package version

`shortRev` doesn't exist if uncommitted changes exist, which is why the
"dirty" fallback exists.
Otherwise this makes it easier to diagnose which version is currently
installed for those installing tms via the flake, and makes it easier to
report issues/regressions if a specific commit can be identified.
`tms --version` output is unaffected.

Author: junglerobba

flake.nix

@@ -44,9 +44,11 @@
               (import rust-overlay)
             ];
           };
+          packageVersion = (fromTOML (builtins.readFile ./Cargo.toml)).package.version;
           rustToolchain = pkgs.pkgsBuildHost.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
           craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchain;
           commonArgs = with pkgs; {
+            version = "${packageVersion}-${self.shortRev or "dirty"}";
             src = craneLib.cleanCargoSource ./.;
             strictDeps = true;