CVAT new UI: add a hint how to delete a point on a polygon

[aschernov]

My actions before raising this issue

• Read/searched the docs
• Searched past issues

Expected Behaviour

Need to have the information that we can delete a point on a polygon using ctrl+double mouse click

Current Behaviour

No information that there is an opportunity to delete a point on a polygon using ctrl+double mouse click. The context menu of a point contains the option "delete point"

Possible Solution

Add a hint description in the context menu near the "delete point" (ctrl+2lmb click)