minor grammar fix

modules/ROOT/pages/performance/index-configuration.adoc

@@ -205,7 +205,7 @@ Unless otherwise specified, the default analyzer is standard-no-stop-words, the
 Used to declare whether full-text indexes should be eventually consistent or not.
 This setting only has effect when a full-text index is created and is remembered as an index-specific setting from then on.
 +
-Indexes usually are fully consistent, and the committing of a transaction returns once both the store and the indexes are updated.
+Indexes are usually fully consistent, and the committing of a transaction returns once both the store and the indexes are updated.
 On the other hand, eventually consistent full-text indexes are not updated as part of the commit; instead, their updates are queued up and applied in a background thread.
 This means there can be a short delay between committing a change and the change becoming visible via any eventually consistent full-text indexes.
 This delay is just an artefact of the queueing and is usually relatively small since.