Insertion of flag values

[nirewen]

PlotSquared Feature Suggestion:

How should it be implemented?

When checking for the plot's flag list (using /plot flag list) you could be able to insert a flag's value into the chat.
When using the use flag, things can get very long and would be very tiring to retype to add a new block to the list. So, Shift+Click the flag value to insert to your already typed /plot flag set use message.

How to implement:
insertion is a key in the JSON, it only accepts a string of text.
{..., "insertion": "flag values", ...}
or using net.md_5.bungee.api.chat.BaseComponent:
component.setInsertion("flag values");
Reference: https://minecraft.gamepedia.com/Raw_JSON_text_format

Additionally, flag values could be autocompleted aswell when setting them.

Additional context

Checklist:

• I made sure there are no duplicates of my suggestion (Use search)
• I made sure my suggestion does not exist yet (Check the wiki)
• I made sure my suggestion is useful for the majority of PlotSquared users

[SirYwell]

You can use /plot flag add use <more types>, that's better than inserting all of the already set values into the chat.

[Citymonstret]

This won't be added. As @SirYwell pointed out, flag values can already be added to list flags by using add rather than set.