Remove reactions feature flag from docs and config

Part of https://github.com/vector-im/riot-web/issues/10282

config.sample.json

@@ -22,8 +22,7 @@
     "showLabsSettings": false,
     "features": {
         "feature_groups": "labs",
-        "feature_pinning": "labs",
-        "feature_reactions": "labs"
+        "feature_pinning": "labs"
     },
     "default_federate": true,
     "default_theme": "light",

docs/labs.md

@@ -29,10 +29,4 @@ Once enabled, send a custom state event to a room to set values:
 
 That's it. Now should see your new counter under the header.
 
-## Reactions
-
-`feature_reactions` allows reacting to messages with emoji and displaying
-reactions from other people. This feature is currently under active development,
-and only portions have been implemented so far.
-
 [#riot-web:matrix.org]: https://matrix.to/#/#riot-web:matrix.org

electron_app/riot.im/config.json

@@ -30,8 +30,7 @@
         }
     },
     "features": {
-        "feature_lazyloading": "enable",
-        "feature_reactions": "enable"
+        "feature_lazyloading": "enable"
     },
     "enable_presence_by_hs_url": {
         "https://matrix.org": false