Update module name to match github

[xeijin]

This is currently causing pkg.dev docs to break for this module

[szermatt]

Thanks! Unfortunately, changing just go.mod doesn't work, as the package name used in the must be consistent with go.mod.
emacsclient-commands isn't a valid package name. I'm not sure what the right solution is.

[szermatt]

I filed issue #6 to remember to fix this problem.