Diagnostics only report one error

[azur1s]

The diagnostics stuff can only report one error (not because the diagnostics is bad, I built it so that it can handle multiple error already) and isn't really helpful when there is multiple error.

This is due to the early returning error in stuff, when it founds the error (e.x. in lowering) it early returns and never continue. I think the fix is to have an Error type and when found an error, return the Error type and continue doing its stuff.