swag: $ sign in router path generates parse error

Describe the bug Our API path includes $ signs, as they’re widely used in the FHIR medical record format. Including the $ signs in the router comment leads to a swag error:

ParseComment error in file main.go :can not parse router comment "/objects$modifier [get]"

To Reproduce Create a main.go file with the following content:

package swag_test

// @id specialObjectList
// @Summary Special objects listing
// @Router /objects$modifier [get]
// @Description A special listing method...
// @Tags Test
func specialObjectList() {
}

Run swag init

Expected behavior To have the /objects$modifier route correctly registered.

Your swag version e.g. 1.7.4

Your go version go1.17.2 darwin/amd64

Desktop (please complete the following information):

• OS: macOS 11.3.1

Additional context I believe #551 was a similar issue; I’d be happy to make a similar PR to add a $ sign into the regex if it would be accepted.