Decoupling capacitor with resistor in series
Some linear regulators are not stable when the ESR of the output capacitor is too low. This can result in oscillations when high-Q ceramic capcitors are used at the output.

The designer may have been concerned this issue applied to the regulator used, and added the series resistor as a solution.

Edit
After reviewing the linked datasheet, this is almost certainly the reason. Note this line on page 207 of the datasheet:



The added one ohm resistor makes up the difference in ESR between the X5R ceramic capacitor chosen for the application circuit (pg. 7) and the 2 ohm minimum for stable operation.