Prometheus unit suffixes are not applied to TYPE and HELP

[dashpole]

Describe the bug

I noticed in the unit test for prometheus:

opentelemetry-java/exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/SerializerTest.java

Lines 141 to 143 in ff79bb7

	+ "# TYPE non_monotonic_cumulative_double_sum gauge\n"
	+ "# HELP non_monotonic_cumulative_double_sum description\n"
	+ "non_monotonic_cumulative_double_sum_seconds{otel_scope_name=\"full\",otel_scope_version=\"version\",type=\"nmcds\"} 5.0 1633950672.000\n"

opentelemetry-java/exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/SerializerTest.java

Lines 70 to 72 in ff79bb7

	+ "# TYPE non_monotonic_cumulative_double_sum gauge\n"
	+ "# HELP non_monotonic_cumulative_double_sum description\n"
	+ "non_monotonic_cumulative_double_sum_seconds{otel_scope_name=\"full\",otel_scope_version=\"version\",type=\"nmcds\"} 5.0 1633950672000\n"

I expect to see unit suffixes on TYPE and HELP comments as well.