search: typeahead js code style improvements

• Affects search/typeahead.js and search/search_parser.js

• Fixes warnings produced by jshint.

• Breakes too long lines.

• Removes unused variables.

• Updates comments.

Reviewed-by: Javier Martin Montull <javier.martin.montull@cern.ch>
Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>