[sv-ac] sv-ac: new proposal to define shortcuts (1466)

The purpose of this change is to define shortcuts as in PSL where:

		delay operator:         ##[+] is equivalent to ##[1:$]
		consecutive repeat:    x[+] is equivalent to x[*1:$]
		delay operator:          ##[*] is equivalent to ##[0:$]
		consecutive repeat:     x[*] is equivalent to x[*0:$]

The complete proposal provided as an attachment to 1466.

Lisa