Added the correct this context to StepOption 'when' functions

[WORMSS]

Update step.d.ts
With accordance to

shepherd/src/js/step.js

Line 332 in ad5b9b0

this.on(event, when[event], this);

the "this" context is set to the Step

[RobbieTheWagner]

@WORMSS I do not know TypeScript very well, but should we also indicate that the this is the step here?

shepherd/src/types/step.d.ts

Line 234 in 99351de

action?: (() => void);

[WORMSS]

Ahh, I was unaware of actions. As the code was not in the JS but in the svelte and I had never used svelte before.
If I am reading this correctly, would it be the tour rather than Step?

shepherd/src/js/components/shepherd-button.svelte

Line 8 in bec705e

action = config.action ? config.action.bind(step.tour) : null;

Which would make the Typescript

- action?: (() => void);
+ action?: ((this: Tour) => void);

[RobbieTheWagner]

@WORMSS yeah, that is correct.