Cell magics not properly handled in VS.Code Jupyter

[timoklimmer]

Environment data

• Language Server version: v2022.9.10
• OS and version: Windows 11, Ubuntu 20.04
• Python version: Python 3.10.5, conda 4.14.0

Repro Steps

1. Create a Jupyter notebook in VS.Code
2. Start a cell with a cells magic, for example %%cmd.
3. Add some arbitrary code to the next lines.

Expected behavior

Whenever a cell's content starts with a cells magic (%%...), the code in the cell is not validated as Python code, and no wrong and disturbing squiggles are shown.

Ignoring all cell content when the cell starts with a %% seems like a good first step.

Actual behavior

Wrong and disturbing squiggles, making a convenient use of cell magics in VS.Code Jupyter impossible.

@debonte fyi See also #2582