don't mention generate in error messages

[Gankra]

iirc one does, but we should pretend init is the only way to run generate

[ashleygwilliams]

@Gankra q on this: init is the interactive configuration thing, assuming i dont want to change my config and want things to generate just from what i have- does generate do this? will it error if i have config incompatible with the current version?

mostly: after not originally seeing it- i see the value of not having to go through the interactive

[Gankra]

generate is responsible for most integrity checks, but init has some more advanced logic on top of it that can help you repair or add missing information, and also handles updating cargo-dist, so I always want to funnel the user into it by default. Nothing prevents you from power-using generate.

[Gankra]

last vestiges of this done in #444