Add swapperoo

[jojo2357]

Fix #3643

Very simple, added tests. Do we want to maybe filter out commands like href whose required args are not interchangeable?

[PHPirates]

Thanks! Looks good, just a few minor things. We should also make sure the intention preview is working (if you hover over the intention name)

Do we want to maybe filter out commands like href whose required args are not interchangeable?

I don't think so, if I for example messed up the order of arguments for href this intention would be really useful to switch them to the correct place

[jojo2357]

I got it working in the ide, but it wont pass any tests.

[PHPirates]

Thanks, you were nearly there! I changed two things:

• When creating a parameter from text, we need to make sure it is actually parsed as a parameter, so it needs to have a command in front of it
• The parameter is a child of the command, not of the command's parent

Please check if I missed any edge cases though.