hgweb: use sysstr to get attribute on diff option Attribute identifier should be `str` not `bytes`.

diff-option: move attributes handling to sysstr Attributes are `str` and should be handled as such.

compression: use sysstr to specify attribute to fetch for priority These are attributes so they should be `str`.

smartset: set attribute using sysstr instead of bytes We do not needs bytes here.

cachedlocalrepo: use sysstr for attribute name of "file of interest" The first item is an attribute name, the second one is a filename. So the first one can (and should) be a `str`.

terse-status: use `sysstr` to specify attributes to set We use unicode string to specify attribute and we add a explicit char for the other usage.

path-suboption: deprecated specifying the attributes as bytes The known suboptions have been updated, so we can deprecated passing bytes in case some extensions use them.

path-suboption: use str for "_pushloc" suboptions That second argument refer to an attribute and do not needs to be bytes.