Update Discovery integration docs (#19405)

* Update discovery.markdown

* Add NETGEAR

source/_integrations/discovery.markdown

@@ -1,6 +1,6 @@
 ---
 title: Discovery
-description: Instructions on how to setup Home Assistant to discover new devices.
+description: Instructions on how to setup Home Assistant to discover new devices with the Discovery integration.
 ha_category:
   - Other
 ha_release: 0.7
@@ -10,36 +10,18 @@ ha_domain: discovery
 
 Home Assistant can discover and automatically configure [zeroconf](https://en.wikipedia.org/wiki/Zero-configuration_networking)/[mDNS](https://en.wikipedia.org/wiki/Multicast_DNS) and [UPnP](https://en.wikipedia.org/wiki/Universal_Plug_and_Play) devices on your network. Currently the `discovery` integration can detect:
 
- * [Apple TV](/integrations/apple_tv/)
- * [Belkin WeMo switches](/integrations/wemo/)
  * [Bluesound speakers](/integrations/bluesound)
  * [Bose Soundtouch speakers](/integrations/soundtouch)
- * [Denon network receivers](/integrations/denonavr/)
  * [DLNA DMR enabled devices](/integrations/dlna_dmr)
  * [Enigma2 media player](/integrations/enigma2)
  * [Frontier Silicon internet radios](/integrations/frontier_silicon)
+ * [LG Soundbars](/integrations/lg_soundbar)
  * [Linn / Openhome](/integrations/openhome)
- * [Logitech Harmony Hub](/integrations/harmony)
  * [Logitech Media Server (Squeezebox)](/integrations/squeezebox)
  * [NETGEAR routers](/integrations/netgear)
- * [Philips Hue](/integrations/hue)
  * [SABnzbd downloader](/integrations/sabnzbd)
- * [Samsung SyncThru Printer](/integrations/syncthru)
- * [Sonos speakers](/integrations/sonos)
  * [Telldus Live](/integrations/tellduslive/)
- * [Wink](/integrations/wink/)
  * [Yamaha media player](/integrations/yamaha)
- * [Yeelight Sunflower bulb](/integrations/yeelightsunflower/)
- * [Xiaomi Gateway (Aqara)](/integrations/xiaomi_aqara/)
-
-It will be able to add Belkin WeMo switches automatically,
-for Philips Hue it will require some configuration from the user.
-
-<div class='note'>
-
-Zeroconf discoverable integrations [Axis](/integrations/axis/)/[ESPHome](/integrations/esphome/)/[HomeKit](/integrations/homekit_controller/)/[Tradfri](/integrations/tradfri/)/[Google Cast](/integrations/cast/) have been migrated to use [zeroconf](/integrations/zeroconf) integration to initiate discovery.
-
-</div>
 
 To load this integration, add the following lines to your `configuration.yaml` file:
 
@@ -47,10 +29,10 @@ To load this integration, add the following lines to your `configuration.yaml` f
 # Example configuration.yaml entry
 discovery:
   ignore:
-    - sonos
-    - samsung_printer
+    - yamaha
+    - logitech_mediaserver
   enable:
-    - homekit
+    - dlna_dmr
 ```
 
 {% configuration discovery %}
@@ -66,28 +48,17 @@ enable:
 
 Valid values for ignore are:
 
- * `apple_tv`: Apple TV
- * `belkin_wemo`: Belkin WeMo switches
  * `bluesound`: Bluesound speakers
  * `bose_soundtouch`: Bose Soundtouch speakers
- * `denonavr`: Denon network receivers
  * `enigma2`: Enigma2 media players
  * `frontier_silicon`: Frontier Silicon internet radios
- * `harmony`: Logitech Harmony Hub
+ * `lg_smart_device`: LG Soundbars
  * `logitech_mediaserver`: Logitech Media Server (Squeezebox)
  * `netgear_router`: NETGEAR routers
- * `octoprint`: Octoprint
  * `openhome`: Linn / Openhome
- * `philips_hue`: Philips Hue
  * `sabnzbd`: SABnzbd downloader
- * `samsung_printer`: Samsung SyncThru Printer
- * `sonos`: Sonos speakers
- * `songpal` : Songpal
  * `tellstick`: Telldus Live
- * `wink`: Wink Hub
  * `yamaha`: Yamaha media player
- * `yeelight`: Yeelight lamps and bulbs (not only Yeelight Sunflower bulb)
- * `xiaomi_gw`: Xiaomi Aqara gateway
 
 Valid values for enable are:
 
@@ -118,7 +89,3 @@ There is currently a <a href='https://web.archive.org/web/20200623234241/https:/
 ### Could not install dependency netdisco
 
 If you see `Not initializing discovery because could not install dependency netdisco==0.6.1` in the logs, you will need to install the `python3-dev` or `python3-devel` package on your system manually (eg. `sudo apt-get install python3-dev` or `sudo dnf -y install python3-devel`). On the next restart of Home Assistant, the discovery should work. If you still get an error, check if you have a compiler (`gcc`) available on your system.
-
-### DSM and Synology
-
-For DSM/Synology, install via debian-chroot [see this forum post](https://community.home-assistant.io/t/error-starting-home-assistant-on-synology-for-first-time/917/15).