[WIP] Add functionality to parse HTML in textbox

[Copilot]

• Analyze the issue and codebase
• Discover HTML textbox functionality already exists in Textbox class
• Create comprehensive documentation on how to use HTML in textboxes
• Create example RDL report demonstrating HTML textbox usage
• Add test cases for HTML textbox functionality
• Update README with HTML textbox feature information

Original prompt

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This section details on the original issue you should resolve

<issue_title>How to parse html on a textbox? Like htmltextbox control on telerik reporting tool.</issue_title>
<issue_description>i have string from rich text control and i need to parse that data on the report.

Thanks.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #149

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