feat(fs-router): change dollar to at in special filenames (#2269) #5399

Job	Run time
Build Java and TypeScript for other tasks	2m 25s
Test Java	3m 43s
Check style	1m 44s
Gradle tests (ubuntu-latest)	3m 36s
ITs (ubuntu-latest, group-1)	4m 25s
Gradle tests (windows-latest)	7m 13s
ITs (ubuntu-latest, group-2)	6m 5s
ITs (windows-latest, some)	7m 1s
Test TypeScript	2m 12s
Tests Summary	13s
	38m 37s

Provide feedback