[Improve Content]: Finish GPPL Page

[SurajSSingh]

Title

Finish creating the MVP of GPPL

Explanations and Details

Update the General-Purpose Programming Language page to include the major sections and code snippets from C#, Python, and Rust (at minimum). Focusing on writing the content for each of the major sections.

Sections to work on

• Introduction

Pre-issue checkboxes

• I have verified that there are no similar open issues already being worked on and can contribute to.
• I have read the appropriate contribution guide before opening this issue.
• I have read Code Of Conduct and will abide by it for this contribution.

[SurajSSingh]

Will need to update the "Sections to work on" portion with additional section names. Maybe possible to have nested task.