Use && for the limit conditions in readuntil

The rest of this file uses && in conditional expressions and reserves
and/or for control flow, so match that.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: hsbt

lib/net/protocol.rb

@@ -215,14 +215,14 @@ def readuntil(terminator, ignore_eof = false, limit: nil)
       offset = @rbuf_offset
       begin
         until idx = @rbuf.index(terminator, offset)
-          if limit and rbuf_size > limit
+          if limit && rbuf_size > limit
             raise ReadLimitExceeded, "terminator not found within #{limit} bytes"
           end
           offset = @rbuf.bytesize
           rbuf_fill
         end
         len = idx + terminator.bytesize - @rbuf_offset
-        if limit and len > limit
+        if limit && len > limit
           raise ReadLimitExceeded, "terminator not found within #{limit} bytes"
         end
         return rbuf_consume(len)