Replace Mouse.isDown docs 
Replace Mouse.isDown docs 

Until Mouse.left and Mouse.right are added as part of #43, it makes sense for the docs on package.elm-lang.org to be true to how the function works to avoid any confusion
Pisys/core,ThomasWeiser/core,martinos/core,rgrempel/core,Pisys/core,simonh1000/core,ThomasWeiser/core,martinos/core,rgrempel/core,simonh1000/core