Many technical documentation websites use search systems that are not accessible using query params and, therefore, useless with bangs. (see for example https://discord.js.org/docs/packages/discord.js/14.25.1)
My suggestion is the ability to create a bang in which the bang field is empty, but the snap field is filled out. And if the bang is used, it is automatically changed to a snap since the bang field is empty.
Another words in the case of discord.js... if I do !djs client, kagi would automatically know that for this bang it has to do a site search instead site:discord.js.org/docs/packages/discord.js/14.25.1 client.
This would reduce wasted time when forgetting and using the bang instead of snap for sites like this.