v0.20.0

This release contains a set of smaller quality of life improvements, especially for SvelteKit users. Last feature update that works in version 2021.1 and below.

• Provide completions for reactive declarations inside Svelte expressions
• Add create variable and create function quick fixes that work from within expressions
• Support sveltekit:prefetch etc. attributes
• Mark file-level SvelteKit config as implicitly used
• Improve missing required attribute inspection for shorthand attributes
• Suppress a lot of misleading inspections
• Change spacing around script tags inserted by the IDE slightly