Add PowerShell Syntax Highlighting

[msr0ot]

Hello RSyntaxTextArea Maintainers,

I'm writing to suggest adding PowerShell syntax highlighting to RSyntaxTextArea. PowerShell is increasingly important for automation and configuration, and its inclusion would benefit developers and enhance the tool's relevance.

I recommend the PowerShell Editor Syntax project on GitHub (https://github.com/PowerShell/EditorSyntax) as a reference for implementing this feature. It provides a detailed overview of PowerShell syntax that could be very useful.

I understand this request involves time and resources, and I'm willing to assist in any way possible, including testing and documentation.

Thank you for considering this addition. I believe it would greatly serve the community and further enrich RSyntaxTextArea's functionality.