Small updates, improvements, and housekeeping to docs (#10405)

* Fix Berkeley mentions

* Add new collectors to list

* Tweak Prometheus/OpenMetrics phrasing

* Fix heading depth in performance guide

* Clarify that exporting starts with Agent start

* Clarify usage of edit-config with new files

* Update images

* service -> systemctl

* Reverse systemctl order

2 files changed, 11 insertions, 6 deletions

diff --git a/collectors/COLLECTORS.md b/collectors/COLLECTORS.md
index de28592ca7..939594e0ce 100644
--- a/collectors/COLLECTORS.md
+++ b/collectors/COLLECTORS.md
@@ -44,7 +44,7 @@ collector—we may be looking for contributions from users such as yourself! If
 -   [System collectors](#system-collectors)
     -   [Applications](#applications)
     -   [Disks and filesystems](#disks-and-filesystems)
-    -   [eBPF (extended Berkely Backet Filter)](#ebpf)
+    -   [eBPF (extended Berkeley Packet Filter)](#ebpf)
     -   [Hardware](#hardware)
     -   [Memory](#memory)
     -   [Networks](#networks)
@@ -64,8 +64,7 @@ configure any of these collectors according to your setup and infrastructure.
 ### Generic
 
 -   [Prometheus endpoints](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/prometheus): Gathers
-    metrics from one or more Prometheus endpoints that use the OpenMetrics exposition format. Autodetects more than 600
-    endpoints.
+    metrics from any number of Prometheus endpoints, with support to autodetect more than 600 services and applications.
 
 ### APM (application performance monitoring)
 
@@ -111,6 +110,8 @@ configure any of these collectors according to your setup and infrastructure.
     database components using `_status/vars` endpoint.
 -   [Consul](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/consul/): Capture service and unbound
     checks status (passing, warning, critical, maintenance). 
+-   [Couchbase](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/couchbase/): Gather per-bucket
+    metrics from any number of instances of the distributed JSON document database.
 -   [CouchDB](/collectors/python.d.plugin/couchdb/README.md): Monitor database health and performance metrics
     (reads/writes, HTTP traffic, replication status, etc).
 -   [MongoDB](/collectors/python.d.plugin/mongodb/README.md): Collect memory-caching system performance metrics and
@@ -118,11 +119,15 @@ configure any of these collectors according to your setup and infrastructure.
 -   [MySQL](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/mysql/): Collect database global,
     replication and per user statistics.
 -   [OracleDB](/collectors/python.d.plugin/oracledb/README.md): Monitor database performance and health metrics.
+-   [Pika](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/pika/): Gather metric, such as clients,
+    memory usage, queries, and more from the Redis interface-compatible database.
 -   [Postgres](/collectors/python.d.plugin/postgres/README.md): Collect database health and performance metrics. 
 -   [ProxySQL](/collectors/python.d.plugin/proxysql/README.md): Monitor database backend and frontend performance
     metrics.
--   [Redis](/collectors/python.d.plugin/redis/): Monitor database status by reading the server's response to the `INFO`
-    command.
+-   [Redis (Go)](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/redis/): Monitor status from any
+    number of database instances by reading the server's response to the `INFO ALL` command.
+-   [Redis (Python)](/collectors/python.d.plugin/redis/): Monitor database status by reading the server's response to
+    the `INFO` command.
 -   [RethinkDB](/collectors/python.d.plugin/rethinkdbs/README.md): Collect database server and cluster statistics.
 -   [Riak KV](/collectors/python.d.plugin/riakkv/README.md): Collect database stats from the `/stats` endpoint.
 -   [Zookeeper](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/zookeeper/): Monitor application
diff --git a/collectors/python.d.plugin/boinc/README.md b/collectors/python.d.plugin/boinc/README.md
index ec06396492..bd509c9004 100644
--- a/collectors/python.d.plugin/boinc/README.md
+++ b/collectors/python.d.plugin/boinc/README.md
@@ -6,7 +6,7 @@ sidebar_label: "BOINC"
 
 # BOINC monitoring with Netdata
 
-Monitors task counts for the Berkely Open Infrastructure Networking Computing (BOINC) distributed computing client using the same RPC interface that the BOINC monitoring GUI does.
+Monitors task counts for the Berkeley Open Infrastructure Networking Computing (BOINC) distributed computing client using the same RPC interface that the BOINC monitoring GUI does.
 
 It provides charts tracking the total number of tasks and active tasks, as well as ones tracking each of the possible states for tasks.