rogez,
You can turn on content assist for JQuery by running the following command in the Terminal+ for your project :
npm i --save @types/jquery
If you are not using npm and do not have package.json in the project, then you can try creating a file named jsconfig.json
in your project directory with the below content to get the content assist :
{
"typeAcquisition": {
"include": [
"jquery"
]
}
}
Hope this helps.
–Swapna
Genuitec Support