Update RuboCop configuration and improve code block filter logic

Author: P-SiZK

.rubocop.yml

@@ -3,9 +3,16 @@ inherit_from: .rubocop_todo.yml
 AllCops:
   NewCops: enable
 
+Layout/LineLength:
+  Enabled: false
+
 Metrics/ClassLength:
   Enabled: false
 
+Naming/PredicatePrefix:
+  ForbiddenPrefixes:
+    - is_
+
 Style/Documentation:
   Enabled: false
 
@@ -15,10 +22,6 @@ Style/EmptyCaseCondition:
 Style/GuardClause:
   Enabled: false
 
-Style/PredicateName:
-  ForbiddenPrefixes:
-    - is_
-
 Style/StringLiterals:
   EnforcedStyle: double_quotes
 
@@ -34,9 +37,6 @@ Style/TrailingCommaInArrayLiteral:
 Style/RedundantPercentQ:
   Enabled: false
 
-Metrics/LineLength:
-  Enabled: false
-
 Metrics/BlockLength:
   Exclude:
     - qiita-markdown.gemspec

lib/qiita/markdown/filters/code_block.rb

@@ -82,7 +82,7 @@ def empty?
           end
 
           def has_only_filename?
-            sections[1].nil? && sections[0] && sections[0].include?(".")
+            sections[1].nil? && sections[0]&.include?(".")
           end
 
           def linguist_language