change toc title

(cherry picked from commit bc2e102)

Author: shuangela

source/usage-examples.txt

@@ -22,7 +22,7 @@ Usage Examples
    Find Operations </usage-examples/find-operations>
    Write Operations </usage-examples/write-operations>
    Bulk Operations </usage-examples/bulkWrite>
-   Monitor Data Changes </usage-examples/changestream>
+   Open a Change Stream </usage-examples/changestream>
    Count Documents Method </usage-examples/count>
    Distinct Field Values </usage-examples/distinct>
    Run a Command </usage-examples/command>