cleanup: remove unnecessary (and potentially problematic) use of 'literal' webhelpers.html.literal (kallithea.lib.helpers.literal) is only needed when the passed string may contain HTML that needs to be interpreted literally. It is unnecessary for plain strings. Incorrect usage of literal can lead to XSS issues, via a malicious user controlling data which will be rendered in other users' browsers. The data could either be stored previously in the system or be part of a forged URL the victim clicks on. For example, when a user browses to a forged URL where a repository changeset or branch name contains a javascript snippet, the snippet was executed when printed on the page using 'literal'. Remaining uses of 'literal' have been reviewed with no apparent problems found. Reported by Bob Hogg <wombat@rwhogg.site> (thanks!).