No water to toilet after the city purged hydrants
If the first comment doesn't work and there is a speedy valve below the toilet;
with two people-

first turn off main water valve.
Open cold water faucet in the affected bath to release the water pressure then close it gently.
With a small bucket at hand, remove the bonnet (valve handle has to be neither all open nor all closed) off the toilet speedy valve
then have the 2nd person open the main valve slightly to purge the toilet line while catching the water in the bucket.
Reassemble bonnet onto valve,
open main valve slowly and test for flow at toilet. Make sure you left the toilet valve in the open position.

Speedy valve: