Declare Net::ReadLimitExceeded

net-protocol 0.3.0 adds it, raised when readuntil does not find the
terminator within the given byte limit.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: dak2

stdlib/net-protocol/0/net-protocol.rbs

@@ -27,6 +27,13 @@ module Net
   class ProtoRetriableError < ProtocolError
   end
 
+  # <!-- rdoc-file=lib/net/protocol.rb -->
+  # ReadLimitExceeded, a subclass of ProtocolError, is raised if the terminator is
+  # not found within the byte limit given to Net::BufferedIO#readuntil.
+  #
+  class ReadLimitExceeded < ProtocolError
+  end
+
   class HTTPBadResponse < StandardError
   end