Relabel search highlights heading

Why these changes are being introduced:

Usability testing indicated that the current search highlights
heading may be confusing to some users.

Relevant ticket(s):

* [GDT-305](https://mitlibraries.atlassian.net/browse/GDT-305)

How this addresses that need:

This relabels the heading as suggested by UXWS.

Side effects of this change:

None.

Author: jazairi

app/views/search/_highlights.html.erb

@@ -1,7 +1,7 @@
 <% highlights = trim_highlights(result) %>
 <% return unless highlights&.any? %>
 
-<h4 class="inner-heading">Other fields matching your search:</h4>
+<h4 class="inner-heading">See full record for all matches to your search terms:</h4>
 <ul class="list-unbulleted truncate-list">
   <% highlights.each do |h| %>
     <% h['matchedPhrases'].each do |phrase| %>