get_current_git_hash breaks when using Jakt as a submodule

[aslilac]

For example, say you've added Jakt as a submodule to a folder named vendor/jakt/

• If you ls vendor/jakt/.git you'll see it's actually just a regular file, not a directory.
• If you cat vendor/jakt/.git you'll see something like...

$ cat vendor/jakt/.git
gitdir: ../../.git/modules/Jakt

So instead of reading "../.git/HEAD", it should actually be reading "../../../.git/modules/Jakt/HEAD".

Similarly, a bit later in the function, instead of "../.git/", the path should be "../../../.git/modules/Jakt/".

[alimpfard]

🤔
So either we make that function more complicated, or add a comptime way to invoke external commands and capture their outputs - I'm not a fan of either option to be honest, maybe we should just let the thing break? it won't cause any real problems besides returning a generic version...