Change the case of error messages to lowercase

[luigimorel]

When I hover over the error messages, i read the error "Error messages should not be capitalized."
I found this stackoverflow thread about formatting errors in Golang: https://stackoverflow.com/questions/68792696/why-error-messages-shouldnt-end-with-a-punctuation-mark-in-go#:~:text=%22Error%20strings%20should%20not%20be,usually%20printed%20following%20other%20context.

Can I create a PR for this?