Fix/pattern escape

[cm-ayf]

This PR fixes control character handling when emitting regex patterns. The list of control characters are obtained from https://json-schema.org/understanding-json-schema/reference/regular_expressions.

Please:

• Make your pull request atomic, fixing one issue at a time unless there are many relevant issues that cannot be decoupled.
• Provide a test case & update the documentation in the Readme.md

[domoritz]

This might be covered by #603 by ahochsteger.

[cm-ayf]

I have confirmed that the issue was resolved. Closing this PR...