Diagnostic reporting (semantic and syntactic checks)

Update autocompletion items based on the spreadsheet created in #638 to better suit using certain functions and to save time for the DFDL developers. These autocompletes will be a case by case and will align with how the spreadsheet is created. Some of these have already been added, so it may be helpful to list those or mark them on the spreadsheet to determine which have not.

Examples of certain custom autocompletes:

name autocompletes to name=""

style autocompletes to style=""

other items like above

This can be done in vscode, but this is separate from intellisense, this can be automatically done whenever there is a change, or can be a ctrl + key combination

Edited 01-29-2026
The VS Code Extension tutorial has example of to provide diagnostics as a way to indicate issue with code. The section labeled "Provide Diagnostics" in this link https://code.visualstudio.com/api/language-extensions/programmatic-language-features contains example code.