Experiment/regex search

[blms]

notes

• regex_search is where the lucene query is built
• get_regex_highlight is where the results are manually highlighted
  • used a bit of regex to get ~150 characters of context before and after the highlight, terminating at line breaks to prevent malformed html
  • also some complicated regex here to allow highlighting matches that span multiple lines, or appear on incomplete lines (i.e. snippet includes an opening or closing li tag but not both)
• right now it's accessible by a separate URL, protected by change_document permissions
  • when available to the public it will likely be a switch on the normal search page, with some help text provided after enabling it
• updated the clean_html method to prevent extra whitespace getting added inside <em> and <li> tags, as it otherwise breaks formatting for highlights
• we're now getting matches across multiple transcriptions on the same document sometimes, so I added a little ellipsis to the template in case that happens
• also added a feature flag and template logic/css for displaying relevance score
• no unit tests yet!

[codecov]

Codecov Report

Attention: Patch coverage is 31.50685% with 50 lines in your changes are missing coverage. Please review.

Project coverage is 98.45%. Comparing base (9a5452a) to head (43750b2).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1588      +/-   ##
===========================================
- Coverage    98.81%   98.45%   -0.36%     
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  Files          238      238              
  Lines        13809    13878      +69     
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+ Hits         13645    13664      +19     
- Misses         164      214      +50