Reword formatDateTime description

Reword formatDateTime description
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cc: @djpmsft
GitHub Issue: https://github.com/MicrosoftDocs/azure-docs/issues/52925

Author: MartinJaffer-MSFT

articles/data-factory/control-flow-expression-language-functions.md

@@ -264,7 +264,7 @@ These functions are useful inside conditions, they can be used to evaluate any t
 | [dayOfMonth](control-flow-expression-language-functions.md#dayOfMonth) | Return the day of the month component from a timestamp. |
 | [dayOfWeek](control-flow-expression-language-functions.md#dayOfWeek) | Return the day of the week component from a timestamp. |
 | [dayOfYear](control-flow-expression-language-functions.md#dayOfYear) | Return the day of the year component from a timestamp. |
-| [formatDateTime](control-flow-expression-language-functions.md#formatDateTime) | Return the date from a timestamp. |
+| [formatDateTime](control-flow-expression-language-functions.md#formatDateTime) | Return the timestamp as a string in optional format. |
 | [getFutureTime](control-flow-expression-language-functions.md#getFutureTime) | Return the current timestamp plus the specified time units. See also [addToTime](control-flow-expression-language-functions.md#addToTime). |
 | [getPastTime](control-flow-expression-language-functions.md#getPastTime) | Return the current timestamp minus the specified time units. See also [subtractFromTime](control-flow-expression-language-functions.md#subtractFromTime). |
 | [startOfDay](control-flow-expression-language-functions.md#startOfDay) | Return the start of the day for a timestamp. |