Fix code smell ArrowFunctionDeclaration
Fix code smell ArrowFunctionDeclaration

There must be exactly 1 whitespace after "fn" keyword.
(SlevomatCodingStandard.Functions.ArrowFunctionDeclaration.IncorrectSpacesAfterKeyword)

We want to use more compact arrow functions, `fn()` instead `fn ()`.
Therefore we set the property of this code smell to 0 spaces after
`fn` instead of 1 space.

hemberger/smr,hemberger/smr,smrealms/smr,smrealms/smr,hemberger/smr,smrealms/smr,hemberger/smr