Fix safe class comparison offenses

Fixes:
- Style/ClassCheck
- Style/ClassEqualityComparison

While `is_a?` and `kind_of?` are equivalent, there is a 5% gain
when switching from class comparison to `intance_of?` 

```
Comparison:
         instance_of: 16902635.9 i/s
    class comparison: 16061288.3 i/s - 1.05x  (± 0.00) slower
```

1 files changed, 0 insertions, 21 deletions

diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 1de00edb..c1d2a7d8 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -77,11 +77,6 @@ Lint/UnusedMethodArgument:
     - 'lib/axlsx/package.rb'
     - 'lib/axlsx/util/validators.rb'
 
-Lint/UselessAssignment:
-  Exclude:
-    - 'lib/axlsx/workbook/worksheet/header_footer.rb'
-    - 'lib/axlsx/workbook/worksheet/sheet_protection.rb'
-
 # Configuration parameters: MinSize.
 Performance/CollectionLiteralInLoop:
   Exclude:
@@ -112,22 +107,6 @@ Style/CaseLikeIf:
   Exclude:
     - 'lib/axlsx/workbook/worksheet/merged_cells.rb'
 
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: is_a?, kind_of?
-Style/ClassCheck:
-  Exclude:
-    - 'lib/axlsx/drawing/axes.rb'
-
-# This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AllowedMethods, AllowedPatterns.
-# AllowedMethods: ==, equal?, eql?
-Style/ClassEqualityComparison:
-  Exclude:
-    - 'lib/axlsx/workbook/worksheet/pane.rb'
-    - 'lib/axlsx/workbook/worksheet/selection.rb'
-    - 'lib/axlsx/workbook/worksheet/sheet_view.rb'
-
 Style/ClassVars:
   Exclude:
     - 'lib/axlsx.rb'