Fallback to not numbering files if amount is large

[aweibell]

Running gs with a lot of modified files results in lots and lots of error messages:

Failed to execute process '/usr/bin/bc'. Reason:
The total size of the argument and environment lists 131kB exceeds the operating system limit of 2MB.
Try running the command again with fewer arguments.
set: Variable name 'modified file path' is not valid. See help identifiers.
~/.config/fish/functions/gs.fish (line 169):
set arr[$i] $name
^
in function “__gs”
called on line 185 of file ~/.config/fish/functions/gs.fish

in function “gs”
called on standard input

The original scm_breeze says

There were more than 150 changed files. SCM Breeze has fallen back to standard git status for performance reasons.