Remove `Word` from the `unix_sigpipe` attribute template so that plain `#[unix_sigpipe]` is not included in suggestions of valid forms of the attribute. Also re-arrange diagnostics code slightly to avoid duplicate diagnostics.
Remove `Word` from the `unix_sigpipe` attribute template so that plain `#[unix_sigpipe]` is not included in suggestions of valid forms of the attribute. Also re-arrange diagnostics code slightly to avoid duplicate diagnostics.