Prometheus exporter `/metrics` endpoint does not produce correct output

[nikitabugrovsky]

Describe the bug

The prometheus exporter /metrics endpoint does not produce correct output for

#TYPE pgagroal_query_count count

That "count" at the end is invalid. It has to be "counter".
Prometheus and the signalfx cannot parse that correctly.

Offending lines are:

pgagroal/src/libpgagroal/prometheus.c

Line 1416 in dc04446

data = pgagroal_append(data, "#TYPE pgagroal_query_count count\n");

pgagroal/src/libpgagroal/prometheus.c

Line 1449 in dc04446

data = pgagroal_append(data, "#TYPE pgagroal_tx_count count\n");

Version

pgagroal 1.5.1