:adhesive_bandage: fix `git init --initial-branch` string instead of bool

[AucaCoyan]

Just using the completions I realized that:

# Create a new git repository
export extern "git init" [
  --initial-branch(-b)                                # initial branch name
  #should be
  --initial-branch(-b): string                        # initial branch name
]

because initial branch takes a string, it not a boolean

[fdncred]

Thanks