fix Guild.widget_image_url

[owocado]

Summary

Hi,

I observed that the URL generated by Guild.widget_image_url() method was missing /api/ parent endpoint, it generates:

https://discord.com/guilds/{guild_id}/widget.png?style={style}

However, as per Discord API docs examples on widget image example, URL should be:

https://discord.com/api/guilds/{guild_id}/widget.png?style={style}

which properly renders as correct widget image.

This PR hopefully fixes this issue. 😅

Checklist

• If code changes were made, then they have been tested
  • I have updated the documentation to reflect the changes
  • I have formatted the code properly by running task lint or pre-commit run --all-files
• This PR fixes an issue
• This PR adds something new (e.g. new method or parameters)
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[shiftinv]

Good catch, thank you!

I suppose this is what I get for not testing it again after changing it :>