convex-backend PR 81: Fix docs: Add missing words in understanding page (#36840)

Was going through the docs and found minor issue. The sentence did not any make sense.

This PR fixes that.

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Co-authored-by: baqirkhan <baqirkhan00@gmail.com>
GitOrigin-RevId: 8688edbaf4b21facb4a25ac009beb45a715ed11c

Author: 2 people

npm-packages/docs/docs/understanding/index.mdx

@@ -36,8 +36,8 @@ connection setup or cluster management.
   needed.
 </Admonition>
 
-The Convex database is reactive. Whenever any data a query depends on changes,
-the query is rerun, and client subscriptions are updated.
+The Convex database is reactive. Whenever any data on which a query depends
+changes, the query is rerun, and client subscriptions are updated.
 
 Convex is a "document-relational" database. "Document" means you put JSON-like
 nested objects into your database. "Relational" means you have tables with