Minor performance improvement for ref finder

Branch names are probably lowercase so using downcase is faster
most of the time. Also prevents re-downcasing the term every
iteration.

app/finders/git_refs_finder.rb

@@ -33,15 +33,21 @@ class GitRefsFinder
   end
 
   def filter_refs_with_prefix(refs, prefix)
-    refs.select { |ref| ref.name.upcase.starts_with?(prefix.upcase) }
+    prefix = prefix.downcase
+
+    refs.select { |ref| ref.name.downcase.starts_with?(prefix) }
   end
 
   def filter_refs_with_suffix(refs, suffix)
-    refs.select { |ref| ref.name.upcase.ends_with?(suffix.upcase) }
+    suffix = suffix.downcase
+
+    refs.select { |ref| ref.name.downcase.ends_with?(suffix) }
   end
 
   def filter_refs_by_name(refs, term)
-    refs.select { |ref| ref.name.upcase.include?(term.upcase) }
+    term = term.downcase
+
+    refs.select { |ref| ref.name.downcase.include?(term) }
   end
 
   def set_exact_match_as_first_result(matches, term)

changelogs/unreleased/ref-finder-performance-improvement.yml

+---
+title: Minor performance improvement for ref finder
+merge_request: 58099
+author:
+type: performance