chore: replace todos with issues (#1066)

agent/usershell/usershell_darwin.go

@@ -3,8 +3,6 @@ package usershell
 import "os"
 
 // Get returns the $SHELL environment variable.
-// TODO: This should use "dscl" to fetch the proper value. See:
-// https://stackoverflow.com/questions/16375519/how-to-get-the-default-shell
 func Get(username string) (string, error) {
 	return os.Getenv("SHELL"), nil
 }