Convert some phutil_escape_html() to hsprintf()

Summary: Found by sgrep_php -e '"...".phutil_escape_html(...)'.

Test Plan:
/
/D1
/uiexample/
/countdown/1/
/herald/transcript/1/all/

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4869