Update source/mapping-rules/mapping-rule-options/time-series.txt

Co-authored-by: Jeff Allen <[email protected]>

Author: ianf-mongodb

source/mapping-rules/mapping-rule-options/time-series.txt

@@ -11,7 +11,7 @@ Configure a Time Series Collection
    :class: singlecol
 
 You can configure mapping rules to migrate a table that contains a 
-datetime column as a :ref:`time series collection <manual-timeseries-collection>`. 
+datetime column to a :ref:`time series collection <manual-timeseries-collection>`. 
 Time series collections efficiently store time series data. In time 
 series collections, writes are organized so that data from the same 
 source is stored alongside other data points from a similar point in time.