`elan toolchain help link` message uses the term "crate"

[simon-dima]

This is most likely left over from when elan was forked from rustup:

elan/src/elan-cli/help.rs

Lines 61 to 62 in 58e8d54

	If you now compile a crate in the current directory, the custom
	toolchain 'master' will be used.";

The help message should be modified to use Lake's terms, I believe "package" would be correct here.