6 files declare their use of SuggestionCollection in Linkit 8.5

ConfigurableDummyMatcher.php in tests/linkit_test/src/Plugin/Linkit/Matcher/ConfigurableDummyMatcher.php

DummyMatcher.php in tests/linkit_test/src/Plugin/Linkit/Matcher/DummyMatcher.php

EmailMatcher.php in src/Plugin/Linkit/Matcher/EmailMatcher.php

EntityMatcher.php in src/Plugin/Linkit/Matcher/EntityMatcher.php

FrontPageMatcher.php in src/Plugin/Linkit/Matcher/FrontPageMatcher.php

SuggestionManager.php in src/SuggestionManager.php