chore: add copyright header

Remove the async naming rule as the tooling does not really work out to detecting the right usage of the `Async` suffix.

README.md

@@ -1,7 +1,7 @@
 # `Geekeey.Extensions.Result`
 
-A .NET library provides a Result<T> type for representing the outcome of operations in C#. It offers a clean and concise
-way to handle success and failure scenarios, promoting better error handling and code readability.
+Result is a .NET library which provides a Result<T> type for representing the outcome of operations in C#. It offers a
+clean and concise way to handle success and failure scenarios, promoting better error handling and code readability.
 
 ## Features