README: Fix/remove broken links

Author: progval

README.md

@@ -15,11 +15,10 @@ Online Site: https://defs.ircdocs.horse/
 * [Channel Type Prefixes](https://defs.ircdocs.horse/defs/chantypes.html)
 * [Client Capabilities](https://defs.ircdocs.horse/defs/clientcaps.html)
 * [CTCP Messages](https://defs.ircdocs.horse/defs/ctcp.html)
-* [Extended Bans](https://defs.ircdocs.horse/defs/extban.html)
+* [Extended Bans](https://defs.ircdocs.horse/defs/extbans.html)
 * [Formatting Characters](https://defs.ircdocs.horse/info/formatting.html)
 * [RPL_ISUPPORT Tokens](https://defs.ircdocs.horse/defs/isupport.html)
 * [Numerics](https://defs.ircdocs.horse/defs/numerics.html)
-* [self-message](https://defs.ircdocs.horse/defs/selfmessage.html)
 * [Server Modes](https://defs.ircdocs.horse/defs/servermodes.html)
 * [Server Notice Masks](https://defs.ircdocs.horse/defs/snomasks.html)
 * [STATS Characters](https://defs.ircdocs.horse/defs/stats.html)