incosistent package name from xontrib module

[doronz88]

Currently, this package is installed and loaded as follows:

xpip install xontrib-brace-expansion
xpip load expand_braces

This is also not reflected correctly in project's documentation and should be refactored to xpip load brace_expansion

I could submit this as a PR if you prefer

[rpdelaney]

Unless there is a convention for xontribs otherwise, I think I'd prefer the code were refactored to match the documentation, rather than the other way around. I'll be happy to review a PR for this if you get to it before I do.

[doronz88]

By refactoring the code to match the documentation so you do agree it should be xpip load brace_expansion

[rpdelaney]

Yes, exactly