fix: always help

[pyqlsa]

Help fails sometimes due to kong.Parse() calling context.go:Context.Reset() early in the function; this call to Context.Reset() makes subsequent calls to model.go:Value.Reset(); Value.Reset() calls Parse for environment variables and default values; Parse in turn calls Value.Mapper.Decode(), which executes the resolver; if the resolver fails, then Parse fails during Reset; originally, --help was implemented as a BeforeApply hook, but due to the above described call order, it wasn't getting called in some failure conditions; if Reset is moved to a later stage in kong.Parse, the hook can be called, allowing for usage to be printed.

Initially opening as a draft, as there may be unintended consequences of moving Reset around in Parse and changing --help to a BeforeResolve hook.

[alecthomas]

I can't think why not, so why not 😀