Implement Spaces() with with strings.Repeat()

Shorter and more efficient.

cmd/micro/util.go

@@ -36,11 +36,7 @@ func NumOccurrences(s string, c byte) int {
 
 // Spaces returns a string with n spaces
 func Spaces(n int) string {
-	var str string
-	for i := 0; i < n; i++ {
-		str += " "
-	}
-	return str
+	return strings.Repeat(" ", n)
 }
 
 // Min takes the min of two ints