feat(chatgpt-nvim): add mappings

[maxbrunet]

📑 Description

This adds the mappings for ChatGPT.nvim: jackMort/ChatGPT.nvim#whichkey-plugin-mappings

I chose the prefix m since c is already taken for "Close buffer" and that places it right after the "Language Tools" in the whichkey menu (l), but I am open to change it for something else if needed

The icon is nf-md-chat (visualize at nerdfonts.com/cheat-sheet)

This also adds the folke/trouble.nvim missing dependency.

ℹ Additional Information

[github-actions[bot]]

Review Checklist

Does this PR follow the [Contribution Guidelines](development guidelines)? Following is a partial checklist:

Proper conventional commit scoping:

• If you are adding a new plugin, the scope would be the name of the category it is being added into. ex. feat(utility): added noice.nvim plugin

• If you are modifying a pre-existing plugin or pack, the scope would be the name of the plugin folder. ex. fix(noice-nvim): fix LSP handler error

• [ ] Pull request title has the appropriate conventional commit type and scope where the scope is the name of the pre-existing directory in the project as described above

• [ ] README is properly formatted and uses fenced in links with <url> unless they are inside a [title](url)

• [ ] Proper usage of opts table rather than setting things up with the config function.