feat(builtins): add numfmt builtin (#922)

Closes #908

Author: chaliy

crates/bashkit/src/builtins/mod.rs

@@ -72,6 +72,7 @@ mod mapfile;
 mod mkfifo;
 mod navigation;
 mod nl;
+mod numfmt;
 mod parallel;
 mod paste;
 mod patch;
@@ -162,6 +163,7 @@ pub use mapfile::Mapfile;
 pub use mkfifo::Mkfifo;
 pub use navigation::{Cd, Pwd};
 pub use nl::Nl;
+pub use numfmt::Numfmt;
 pub use parallel::Parallel;
 pub use paste::Paste;
 pub use patch::Patch;