[Refactor] Split functions out to file (#713)

Splits code out from `LGraphCanvas`.

src/litegraph.ts

@@ -87,6 +87,7 @@ export interface LGraphNodeConstructor<T extends LGraphNode = LGraphNode> {
 
 // End backwards compat
 
+export { isOverNodeInput, isOverNodeOutput } from "./canvas/measureSlots"
 export { CanvasPointer } from "./CanvasPointer"
 export { ContextMenu } from "./ContextMenu"
 export { CurveEditor } from "./CurveEditor"