Update word list for spell check.

Author: aaugustin

docs/spelling_wordlist.txt

@@ -5,33 +5,47 @@ awaitable
 aymeric
 backpressure
 Backpressure
+balancer
+balancers
 Bitcoin
+bottlenecked
 bufferbloat
 Bufferbloat
 bugfix
 bytestring
 bytestrings
 changelog
+coroutine
+coroutines
+cryptocurrencies
 cryptocurrency
+Ctrl
 daemonize
 fractalideas
 iterable
 keepalive
 KiB
 lifecycle
 Lifecycle
+lookups
 MiB
 nginx
+parsers
 permessage
 pong
 pongs
 Pythonic
 serializers
+Subclasses
+subclasses
 subclassing
 subprotocol
 subprotocols
+Tidelift
 TLS
+tox
 Unparse
+unregister
 uple
 username
 websocket