print: avoid strings.Count calls unless needed
print: avoid strings.Count calls unless needed

name      old time/op    new time/op    delta
Fprint-4    12.7µs ± 2%    12.4µs ± 1%  -2.36%          (p=0.004 n=6+5)

mvdan/sh,mvdan/sh,mvdan/sh,mvdan/sh