Added instructions on how to download the signature file using wget, and fixed a typo in the wget commands that would have caused the command to fail when copied/pasted.
Reviewed-on: https://gitea.com/gitea/docs/pulls/262
Reviewed-by: Lunny Xiao <[email protected]>
Co-authored-by: kmanwar89 <[email protected]>
Co-committed-by: kmanwar89 <[email protected]>
