Remove remaining easy rubocop suppressions (#879)

Removes the remaining "easy to fix" rubocop suppressions from the
asciidoctor extension code base.

Author: nik9000

resources/asciidoctor/.rubocop.yml

@@ -5,9 +5,6 @@ inherit_from: ../../.rubocop.yml
 Layout/AlignParameters:
   Enabled: false
 
-Layout/BlockAlignment:
-  Enabled: false
-
 Layout/IndentArray:
   Enabled: false
 
@@ -17,14 +14,5 @@ Metrics/AbcSize:
 Metrics/BlockLength:
   Enabled: false
 
-Metrics/BlockNesting:
-  Enabled: false
-
 Metrics/MethodLength:
   Enabled: false
-
-Metrics/PerceivedComplexity:
-  Enabled: false
-
-Style/NestedParenthesizedCalls:
-  Enabled: false

resources/asciidoctor/lib/copy_images/extension.rb

@@ -46,7 +46,7 @@ def process_block(block)
     def process_block_image(block)
       return unless block.context == :image
 
-      uri = block.image_uri(block.attr 'target')
+      uri = block.image_uri(block.attr('target'))
       process_image block, uri
     end