Update docs with new known_events path

  - Use common.yml as events definition example
  - Update docs, comments and examples to point to
    know_events folder

doc/development/product_analytics/usage_ping.md

@@ -270,7 +270,7 @@ Implemented using Redis methods [PFADD](https://redis.io/commands/pfadd) and [PF
 
 ##### Adding new events
 
-1. Define events in [`known_events.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events.yml).
+1. Define events in [`known_events`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events/).
 
    Example event:
 
@@ -412,7 +412,7 @@ w
 
 1. Track events using JavaScript/Vue API helper which calls the API above
 
-   Example usage for an existing event already defined in  [known events](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events.yml):
+   Example usage for an existing event already defined in [known events](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events/):
 
    Note that `usage_data_api` and `usage_data_#{event_name}` should be enabled in order to be able to track events
 
@@ -447,7 +447,7 @@ Recommendations:
 
 ##### Known events in usage data payload
 
-All events added in [`known_events.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events.yml) are automatically added to usage data generation under the `redis_hll_counters` key. This column is stored in [version-app as a JSON](https://gitlab.com/gitlab-services/version-gitlab-com/-/blob/master/db/schema.rb#L209).
+All events added in [`known_events/common.yml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events/common.yml) are automatically added to usage data generation under the `redis_hll_counters` key. This column is stored in [version-app as a JSON](https://gitlab.com/gitlab-services/version-gitlab-com/-/blob/master/db/schema.rb#L209).
 For each event we add metrics for the weekly and monthly time frames, and totals for each where applicable:
 
 - `#{event_name}_weekly`: Data for 7 days for daily [aggregation](#adding-new-events) events and data for the last complete week for weekly [aggregation](#adding-new-events) events.
@@ -493,7 +493,7 @@ Example usage:
 redis_usage_data(Gitlab::UsageDataCounters::WikiPageCounter)
 redis_usage_data { ::Gitlab::UsageCounters::PodLogs.usage_totals[:total] }
 
-# Define events in known_events.yml https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events.yml
+# Define events in common.yml https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage_data_counters/known_events/common.yml
 
 # Tracking events
 Gitlab::UsageDataCounters::HLLRedisCounter.track_event(visitor_id, 'expand_vulnerabilities')

lib/gitlab/usage_data_counters/aggregated_metrics/common.yml

@@ -3,7 +3,7 @@
 #             - "ANY": counts unique elements that were observed triggering any of following events
 #             - "ALL": counts unique elements that were observed triggering all of following events
 #  events: list of events names to aggregate into metric. All events in this list must have the same 'redis_slot' and 'aggregation' attributes
-#           see from lib/gitlab/usage_data_counters/known_events.yml for the list of valid events.
+#           see from lib/gitlab/usage_data_counters/known_events/common.yml for the list of valid events.
 ---
 - name: product_analytics_test_aggregated_metrics
   operator: ANY

lib/gitlab/usage_data_counters/hll_redis_counter.rb

@@ -25,7 +25,7 @@ module Gitlab
       # Track event on entity_id
       # Increment a Redis HLL counter for unique event_name and entity_id
       #
-      # All events should be added to know_events file lib/gitlab/usage_data_counters/known_events.yml
+      # All events should be added to know_events yml files lib/gitlab/usage_data_counters/known_events/
       #
       # Event example:
       #