Update default plain text mask to include .config and markdown files

[jonesbusy]

What's changed?

The default list of plain text mask

What's your motivation?

Rewriting mardown files and .config extension (for example .mvn/maven.config or .mvn/jvm.config)

Have you considered any alternatives or workarounds?

Directly override the plainTextMasks on the plugin config. But I think having those default is a valid use case.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've added the license header to any new files through ./gradlew licenseFormat
• I've used the IntelliJ IDEA auto-formatter on affected files
• I've updated the documentation (if applicable)

Doc is : openrewrite/rewrite-docs#231

Also the list was not up-to-date

[timtebeek]

Thanks for the suggestion! Should become available in the next release. You can try this out through our latest snapshots once we resolve the build issues on the main branch.