chore: Fixed comment about transaction_tracer.transaction_threshold

[jsumners-nr]

This PR fixes a comment in our configuration defaults. Basically, the comment had the intention inverted. The best documentation I could find to verify the configuration setting in general is in the Java agent's code -- https://github.com/newrelic/newrelic-java-agent/blob/a4187358aeeda79d9b9d0b7ca87faf378bd35d82/newrelic-agent/src/main/resources/newrelic.yml#L195-L213. This meshes with our actual implementation:

node-newrelic/lib/transaction/trace/aggregator.js

Lines 231 to 292 in 46924e5

	isBetter(name, duration, apdexT) {
	/* 1. If the transaction duration is below the tracing threshold, the
	* transaction is skipped.
	*
	* The threshold for slow traces defaults to apdex_f, which is 4 * apdex_t.
	*/
	const config = this.config.transaction_tracer
	let isOverThreshold
	if (
	config &&
	config.transaction_threshold != null &&
	config.transaction_threshold !== 'apdex_f' &&
	typeof config.transaction_threshold === 'number'
	) {
	isOverThreshold = duration >= config.transaction_threshold * TO_MILLIS
	} else {
	isOverThreshold = duration >= 4 * TO_MILLIS * apdexT
	}
	if (!isOverThreshold) {
	return false
	}
	/* 2. If the transaction duration is less than the duration of the current
	* slow transaction, the transaction is skipped.
	*/
	let slowerThanExisting = true
	if (this.trace) {
	slowerThanExisting = this.trace.getDurationInMillis() < duration
	}
	if (!slowerThanExisting) {
	return false
	}
	/* We always gather some slow transactions at the start, regardless of
	* the size of Top N. This changes the behavior of the rest of the
	* decision-making process in some subtle ways.
	*/
	const hasMetGuarantee = this.reported >= 5
	/* 3. If the transaction's name is in the transaction map and its duration
	* is less than the response time in the map, it is skipped.
	*/
	let slowerThanCaptured = true
	if (hasMetGuarantee && this.requestTimes[name]) {
	slowerThanCaptured = this.requestTimes[name] < duration
	}
	if (!slowerThanCaptured) {
	return false
	}
	/* Not part of enumerated rules, but necessary for Top N support:
	* Ensure this name is either already in the request time map
	* or that the map still hasn't hit capacity.
	*/
	return !(
	hasMetGuarantee &&
	!this.requestTimes[name] &&
	Object.keys(this.requestTimes).length >= this.capacity
	)
	}
	}

The Python agent's documentation concurs -- https://docs.newrelic.com/docs/apm/agents/python-agent/configuration/python-agent-configuration/#txn-tracer-threshold