Lower chathistory size limit

It takes over 30-60s for Synapse (matrix.org and my own HS) to fetch 500
items of history in plenty of rooms, so we need to severely limit such
requests or everything gets stuck and crashy.

Author: progval

lib/irc/handler.ex

@@ -602,7 +602,7 @@ defmodule M51.IrcConn.Handler do
       "CLIENTTAGDENY=*,-draft/react,-draft/reply",
       "CHANLIMIT=",
       "CHANTYPES=#!",
-      "CHATHISTORY=1000",
+      "CHATHISTORY=100",
       "MAXTARGETS=1",
       # https://github.com/ircv3/ircv3-specifications/pull/510
       "MSGREFTYPES=msgid",

test/irc/handler_test.exs

@@ -20,7 +20,7 @@ defmodule M51.IrcConn.HandlerTest do
 
   @cap_ls_302 ":server. CAP * LS :account-tag batch draft/account-registration=before-connect draft/channel-rename draft/chathistory draft/message-redaction draft/multiline=max-bytes=8192 draft/sasl-ir echo-message extended-join labeled-response message-tags sasl=PLAIN server-time soju.im/account-required standard-replies userhost-in-names\r\n"
   @cap_ls ":server. CAP * LS :account-tag batch draft/account-registration draft/channel-rename draft/chathistory draft/message-redaction draft/multiline draft/sasl-ir echo-message extended-join labeled-response message-tags sasl server-time soju.im/account-required standard-replies userhost-in-names\r\n"
-  @isupport "CASEMAPPING=rfc3454 CLIENTTAGDENY=*,-draft/react,-draft/reply CHANLIMIT= CHANTYPES=#! CHATHISTORY=1000 MAXTARGETS=1 MSGREFTYPES=msgid PREFIX= TARGMAX=JOIN:1,PART:1 UTF8ONLY :are supported by this server\r\n"
+  @isupport "CASEMAPPING=rfc3454 CLIENTTAGDENY=*,-draft/react,-draft/reply CHANLIMIT= CHANTYPES=#! CHATHISTORY=100 MAXTARGETS=1 MSGREFTYPES=msgid PREFIX= TARGMAX=JOIN:1,PART:1 UTF8ONLY :are supported by this server\r\n"
 
   setup do
     start_supervised!({MockMatrixClient, {self()}})