Typescript compilation errors and linting warning in Etch-A-Sketch example

[cjnix35]

I've encountered some issues with the Typescript compilation and a linting warning in the Etch-A-Sketch SolidJS example code. Here are the details:

1. Typescript error: The type definition for the style attribute seems incorrect. The error message is:

   • Type '{ display: string; "grid-template-rows": string; "grid-template-columns": string; }' is not assignable to type 'string | CSSProperties | undefined'.

2. Typescript error: The render function is receiving a null type argument which is not compatible with its expected parameter type. The error message is:

   • Argument of type 'HTMLElement | null' is not assignable to parameter of type 'MountableElement'.

3. ESLint warning: The code has an empty div component which is not self-closing, raising a lint warning:

   • Empty components are self-closing.
   • This is a minor issue but could be improved for better code quality.