Fix typos with codespell

Using codespell 2.0.0.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
curvelinear
dof
doubleclick
fave
findn
GIRD
leapyear
lod
merchantibility
nd
numer
ois
ony
que
seeked
synching
te
uint
unselect
webp
EOF

$ codespell -w -q 3 -I ../godot-word-whitelist.txt --skip="./thirdparty,*.po"
$ git diff // undo unwanted changes
```

modules/webrtc/doc_classes/WebRTCPeerConnection.xml

@@ -48,7 +48,7 @@
 				Valid [code]options[/code] are:
 				[codeblock]
 				{
-				    "negotiated": true, # When set to true (default off), means the channel is negotiated out of band. "id" must be set too. data_channel_received will not be called.
+				    "negotiated": true, # When set to true (default off), means the channel is negotiated out of band. "id" must be set too. "data_channel_received" will not be called.
 				    "id": 1, # When "negotiated" is true this value must also be set to the same value on both peer.
 
 				    # Only one of maxRetransmits and maxPacketLifeTime can be specified, not both. They make the channel unreliable (but also better at real time).