Before it:

• didn't open when alt+f1 was invoked in the merge editor
• included a non-existent command
• didn't provide keybindings for commands (follow suit with other help dialogs)
• didn't include various helpful commands
• included comment info, unrelated to this dialog

Now it:

• actually shows up when alt+f1 is invoked in a merge editor
• provides the keybindings (all currently unassigned) to users, allowing them to configure them
• removes a non-existent command in favor of the actual ones
• removes unnecessary comment info from the dialog

fixes #244656
fixes #227844