docs: Improve code overview section

The cilium section here was including non-agent cilium components such
as the bpf datapath and plugins, so rename it. While we're at it, add
some other non-agent components that were previously missed.

Signed-off-by: Joe Stringer <joe@cilium.io>

Documentation/contributing/development/codeoverview.rst

@@ -23,6 +23,9 @@ api
 bpf
   The BPF datapath code
 
+bugtool
+  CLI for collecting agent & system information for bug reporting
+
 cilium
   Cilium CLI client
 
@@ -55,8 +58,8 @@ plugins
 test
   End-to-end integration tests run in the :ref:`testsuite`.
 
-Cilium-agent
-------------
+Cilium
+------
 
 api/v1/openapi.yaml
   API specification of the Cilium API. Used for code generation.
@@ -67,6 +70,12 @@ api/v1/models/
 bpf
   The BPF datapath code
 
+cilium
+  Cilium CLI client
+
+cilium-health
+  Cilium cluster connectivity CLI client
+
 daemon
   cilium-agent specific code
 
@@ -85,6 +94,9 @@ Hubble CLI can be found in the separate repository `github.com/cilium/hubble
 separate repository `github.com/cilium/hubble-ui
 <https://github.com/cilium/hubble-ui>`_.
 
+api/v1/external, api/v1/flow, api/v1/observer, api/v1/peer, api/v1/relay
+  API specifications of the Hubble APIs.
+
 hubble-relay
   Hubble relay agent