wifi: Update documentation

RELEASE_NOTES

@@ -37,6 +37,7 @@ New user-visible features
 - (config-store) New ConfigStore::SaveDeprecated Attribute (default false) to avoid to save DEPRECATED attributes.
 - (core) Add TracedCallback::IsEmpty to know if a TracedCallback has any callback associated.
 - (core) Add std::hash<ns3::Ptr<T>> to allow seamless use of Ptr as key in unordered_maps.
+- (wifi) Add support for 11ax MU EDCA Parameter Set.
 
 Bugs fixed
 ----------

src/wifi/doc/source/wifi-design.rst

@@ -22,7 +22,7 @@ on the IEEE 802.11 standard [ieee80211]_. We will go into more detail below but
 * basic 802.11 DCF with **infrastructure** and **adhoc** modes
 * **802.11a**, **802.11b**, **802.11g**, **802.11n** (both 2.4 and 5 GHz bands), **802.11ac** and **802.11ax** (2.4, 5 and 6 GHz bands) physical layers
 * **MSDU aggregation** and **MPDU aggregation** extensions of 802.11n, and both can be combined together (two-level aggregation)
-* 802.11ax **DL OFDMA** and **UL OFDMA**
+* 802.11ax **DL OFDMA** and **UL OFDMA** (including support for the MU EDCA Parameter Set)
 * QoS-based EDCA and queueing extensions of **802.11e**
 * the ability to use different propagation loss models and propagation delay models,
   please see the chapter on :ref:`Propagation` for more detail
@@ -164,7 +164,7 @@ packets.  Interference from other wireless technologies is only modeled
 when the SpectrumWifiPhy is used.
 The following details pertain to the physical layer and channel models:
 
-* 802.11ax MU-RTS/CTS and the MU EDCA Parameter set are not yet supported
+* 802.11ax MU-RTS/CTS is not yet supported
 * 802.11ac/ax MU-MIMO is not supported, and no more than 4 antennas can be configured
 * 802.11n/ac/ax beamforming is not supported
 * 802.11n RIFS is not supported