Attribute draggable is not boolean

[brunnerh]

Describe the bug
draggable has three states, "true", "false" and auto (missing value). Currently that is flagged as an error when TypeScript checking/preprocessing is active.

(JSX attribute) svelte.JSX.HTMLAttributes<HTMLDivElement>.draggable?: boolean
Type 'string' is not assignable to type 'boolean'.ts(2322)

This might just require a type change in svelte-jsx.d.ts to something like the type of contenteditable ("true" | "false" | boolean).

To Reproduce

Example component:

<script type="text/typescript">
</script>

<div draggable="true"/>

Expected behavior
Values "true" and "false" are accepted.

System (please complete the following information):

• OS: Windows 10, 64bit
• IDE: VSCode
• Plugin/Package: Svelte for VSCode

Workaround

Interpolate boolean:

<div draggable={true}/>

[dummdidumm]

Same reason as #366 , only for booleans instead of numbers. Edit: Not quite. Seems it's generally wrong to add attr="true" on boolean attributes, it should be either attr or attr="attr" for the true case, and leave it out for the false case. draggable seems to be a special cause however, where the attributes are actually an enum with the values true/false/auto. So it would say we go with your suggestion to just enhance the typings of this one attribute.