Previously variable declaration required a keyword, e.g. ```kcl let x = 4 const x = 4 var x = 4 ``` These were all valid, and did the exact same thing. As of this PR, they're all still valid, but the KCL formatter will change them all to just: ```kcl x = 4 ``` which is the new preferred way to declare a constant. But the formatter will remove the var/let/const keywords. Closes https://github.com/KittyCAD/modeling-app/issues/3985