Bugfix/editorconfig bug

[jamie-taylor-rjj]

Rationale for this PR

This PR fixes #153 by fixing a very silly mistake. See if you can spot it:

// problematic line:
public class SecureHeadersMiddleware()

// fixed line:
public class SecureHeadersMiddleware

The problematic code was added when following a Rider suggestion to replace the constructor with a Primary constructor. This lead to the inclusion of the parenthesis after the class name, which seems to have had a cascading affect on the way that the .editorconfig saw the file.

There's certainly something in the .editorconfig which is at odds with primary constructors, but that's a problem for another day.

PR Checklist

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Essential

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• [:question: ] I have added tests to the OwaspHeaders.Core.Tests project
• [:white_check_mark: ] I have run the dotnet-format command and fixed any .editorconfig issues
• [:white_check_mark: ] I have ensured that the code coverage has not dropped below 65%
• [:white_check_mark: ] I have increased the version number in OwaspHeaders.Core.csproj (only relevant for code changes)

Optional

• [:question: ] I have documented the new feature in the docs directory
• [:question: ] I have provided a code sample, showing how someone could use the new code

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[GaProgMan]

LGTM

[GaProgMan]

Looks like this was related to dotnet/format#2165, which makes me feel much better about having missed the cause in the first place.