Document that telemetry is not available on Windows.

Add notes to the WSGITelemetryService, WSGISlowRequests and
WSGITelemetryOptions directive references and the external telemetry
service user guide, matching how the daemon mode directives already
document their unavailability on Windows.

Author: GrahamDumpleton

docs/configuration-directives/WSGISlowRequests.rst

@@ -27,6 +27,10 @@ Setting ``WSGISlowRequests`` without ``WSGITelemetryService`` is
 not treated as a configuration error: the per-request bookkeeping
 runs and the records are constructed, but nothing reads them.
 
+Note that, like the telemetry reporter it feeds, this directive is
+not available on Windows. See :doc:`WSGITelemetryService` for
+details.
+
 Each slow-request record carries:
 
 * The originating process PID and worker thread ID.

docs/configuration-directives/WSGITelemetryOptions.rst

@@ -16,6 +16,10 @@ This is a server-wide directive: it may only appear at the top
 level of the Apache configuration, outside any ``<VirtualHost>``
 block.
 
+Note that, like the telemetry reporter it configures, this directive
+is not available on Windows. See :doc:`WSGITelemetryService` for
+details.
+
 Syntax follows the Apache ``Options`` directive convention. Two
 argument forms are supported, and may not be mixed within one
 line:

docs/configuration-directives/WSGITelemetryService.rst

@@ -39,6 +39,14 @@ configuration line enables the reporter for the entire Apache
 instance, covering every daemon process group and every
 embedded-mode Apache child.
 
+Note that the telemetry reporter, and so the ``WSGITelemetryService``,
+:doc:`WSGISlowRequests` and :doc:`WSGITelemetryOptions` directives, are
+not available on Windows. The reporter delivers its datagrams over a
+UNIX ``SOCK_DGRAM`` socket, which Windows does not provide, so the
+feature is not built there and these directives are not registered.
+Using one of them on Windows is reported by Apache as an unknown
+directive.
+
 Arguments
 ---------
 

docs/user-guides/external-telemetry-service.rst

@@ -34,6 +34,14 @@ using the operating-system ``mod_wsgi`` package (or any other
 manually-configured Apache) can use the telemetry pipeline without
 adopting ``mod_wsgi-express`` as well.
 
+.. note::
+
+   The telemetry reporter is not available on Windows. It delivers its
+   datagrams over a UNIX ``SOCK_DGRAM`` socket, which Windows does not
+   provide, so the feature is not built there and the
+   ``WSGITelemetryService``, ``WSGISlowRequests`` and
+   ``WSGITelemetryOptions`` directives are not registered.
+
 How it works
 ------------