Add more escapes

Signed-off-by: Felix Yuan <felix.yuan@reddit.com>

Author: Sticksman

collector/collector_test.go

@@ -49,6 +49,7 @@ func readMetric(m prometheus.Metric) MetricResult {
 func sanitizeQuery(q string) string {
 	q = strings.Join(strings.Fields(q), " ")
 	q = strings.Replace(q, "(", "\\(", -1)
+	q = strings.Replace(q, "?", "\\?", -1)
 	q = strings.Replace(q, ")", "\\)", -1)
 	q = strings.Replace(q, "[", "\\[", -1)
 	q = strings.Replace(q, "]", "\\]", -1)