Fix Naming/PredicateMethod cop.

 * Correct name of `Decompressor#eof?` and swap the alias.
 * Allow Libbz2 to return booleans from `!` methods.

Author: hainesr

.rubocop.yml

@@ -17,3 +17,8 @@ Layout/LineLength:
 
 Metrics/MethodLength:
   Max: 15
+
+# Allow `!` methods in this file to return boolean values.
+Naming/PredicateMethod:
+  Exclude:
+    - 'lib/zip/bzip2/libbz2.rb'

lib/zip/bzip2/decompressor.rb

@@ -20,11 +20,11 @@ def read(length = nil, outbuf = +'')
         outbuf.replace(@buffer.slice!(0...(length || @buffer.bytesize)))
       end
 
-      def eof
+      def eof?
         @buffer.empty? && input_finished?
       end
 
-      alias eof? eof
+      alias eof eof?
 
       private