[DOCS] Relocate `transport` module content (#55472) (#57425)

Moves `transport` content from the [Modules][0] section to the
[Configuring Elasticsearch][1] section.

Supporting changes:
* Adds explicit anchors to several headings
* Changes several headings to sentence case
* Increments several headings
* Removes several unneeded `[float]` attributes
* Replaces `transport module` with `transport layer`

Relates to #53305

[0]: https://www.elastic.co/guide/en/elasticsearch/reference/master/modules.html
[1]: https://www.elastic.co/guide/en/elasticsearch/reference/master/settings.html

docs/reference/modules.asciidoc

@@ -50,11 +50,6 @@ The modules in this section are:
 
     Information about the dedicated thread pools used in Elasticsearch.
 
-<<modules-transport,Transport>>::
-
-    Configure the transport networking layer, used internally by Elasticsearch
-    to communicate between nodes.
-
 <<modules-cross-cluster-search, {ccs-cap}>>::
 
     {ccs-cap} enables executing search requests across more than one cluster
@@ -75,5 +70,3 @@ include::modules/network.asciidoc[]
 include::modules/node.asciidoc[]
 
 include::modules/threadpool.asciidoc[]
-
-include::modules/transport.asciidoc[]

docs/reference/modules/transport.asciidoc

@@ -1,9 +1,9 @@
 [[modules-transport]]
-== Transport
+=== Transport
 
-The transport module is used for internal communication between nodes
+The transport networking layer is used for internal communication between nodes
 within the cluster. Each call that goes from one node to the other uses
-the transport module (for example, when an HTTP GET request is processed
+the transport layer (for example, when an HTTP GET request is processed
 by one node, and should actually be processed by another node that holds
 the data). The transport module is also used for the `TransportClient` in the
 {es} Java API.
@@ -15,8 +15,8 @@ http://en.wikipedia.org/wiki/C10k_problem[C10k problem], as well as
 being the ideal solution for scatter (broadcast) / gather operations such
 as search in Elasticsearch.
 
-[float]
+[[transport-settings]]
-=== Transport Settings
+==== Transport settings
 
 The internal transport communicates over TCP. You can configure it with the
 following settings:
@@ -57,8 +57,8 @@ transport connections.
 It also uses the common
 <<modules-network,network settings>>.
 
-[float]
+[[transport-profiles]]
-==== Transport Profiles
+===== Transport profiles
 
 Elasticsearch allows you to bind to multiple ports on different interfaces by
 the use of transport profiles. See this example configuration
@@ -106,8 +106,8 @@ example above:
 * `tcp.send_buffer_size`: Configures the send buffer size of the socket
 * `tcp.receive_buffer_size`: Configures the receive buffer size of the socket
 
-[float]
+[[long-lived-connections]]
-==== Long-lived idle connections
+===== Long-lived idle connections
 
 Elasticsearch opens a number of long-lived TCP connections between each pair of
 nodes in the cluster, and some of these connections may be idle for an extended
@@ -120,11 +120,9 @@ and ensuring that the keepalive interval is shorter than any timeout that might
 cause idle connections to be closed, or by setting `transport.ping_schedule` if
 keepalives cannot be configured.
 
-[float]
-==== Transport Compression
 
-[float]
+[[request-compression]]
-===== Request Compression
+===== Request compression
 
 By default, the `transport.compress` setting is `false` and network-level
 request compression is disabled between nodes in the cluster. This default
@@ -139,8 +137,8 @@ request compression, you can set it on a per-remote cluster basis using the
 <<remote-cluster-settings,`cluster.remote.${cluster_alias}.transport.compress` setting>>.
 
 
-[float]
+[[response-compression]]
-===== Response Compression
+===== Response compression
 
 The compression settings do not configure compression for responses. {es} will
 compress a response if the inbound request was compressed--even when compression
@@ -148,10 +146,10 @@ is not enabled. Similarly, {es} will not compress a response if the inbound
 request was uncompressed--even when compression is enabled.
 
 
-[float]
+[[transport-tracer]]
-=== Transport Tracer
+==== Transport tracer
 
-The transport module has a dedicated tracer logger which, when activated, logs incoming and out going requests. The log can be dynamically activated
+The transport layer has a dedicated tracer logger which, when activated, logs incoming and out going requests. The log can be dynamically activated
 by setting the level of the `org.elasticsearch.transport.TransportService.tracer` logger to `TRACE`:
 
 [source,console]

docs/reference/setup.asciidoc

@@ -81,6 +81,8 @@ include::settings/sql-settings.asciidoc[]
 
 include::settings/transform-settings.asciidoc[]
 
+include::modules/transport.asciidoc[]
+
 include::settings/notification-settings.asciidoc[]
 
 include::setup/important-settings.asciidoc[]