Fix Style/SymbolProc offenses

This also provides a performance improvement

```
Comparison (array of 4 elements):
              map(&):  3643131.4 i/s
              map {}:  3488052.5 i/s - 1.04x  (± 0.00) slower

Comparison (array of 20 elements):
              map(&):   466013.9 i/s
              map {}:   408447.2 i/s - 1.14x  (± 0.00) slower
```

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/axlsx/workbook/worksheet/worksheet.rb b/lib/axlsx/workbook/worksheet/worksheet.rb
index aaeadb11..1ece3138 100644
--- a/lib/axlsx/workbook/worksheet/worksheet.rb
+++ b/lib/axlsx/workbook/worksheet/worksheet.rb
@@ -760,7 +760,7 @@ module Axlsx
       raise ArgumentError, (ERR_SHEET_NAME_CHARACTER_FORBIDDEN % name) if WORKSHEET_NAME_FORBIDDEN_CHARS.any? { |char| name.include? char }
 
       name = Axlsx::coder.encode(name)
-      sheet_names = @workbook.worksheets.reject { |s| s == self }.map { |s| s.name }
+      sheet_names = @workbook.worksheets.reject { |s| s == self }.map(&:name)
       raise ArgumentError, (ERR_DUPLICATE_SHEET_NAME % name) if sheet_names.include?(name)
     end