fix: invalid syntax for ClassAutoAccessorDescriptor

add a colon immediately following to the `value#set` property prior to this change, this type would be considered invalid typescript syntax > Parameter 'value' of exported function has or is using private name ''.(4078) >'=>' expected.(1005) TS Playground showing the errors surfaced by the type checker: https://www.typescriptlang.org/play?target=99#code/C4TwDgpgBAwgNgQwM5IIIFdgHtUGNcQpYBOAIhLiQtsVALxQAUAUFFAG4JzoQBcUAb1ZsoAcwjB+jAJT0AfFHQA7ANZKsAdyUBuYWyQSpnbn0Wr1W6f3ZYAlgBNdbAL4AaYZSXAIAD0mC9KBVbJXt+ACIEfEIkEnCnESUEAFtTJGBiENEoAB8oJBBkgCMsOAS2KIIUfgExCRl+ZTVNJVd8+uMeRvMWqw47eyhncvzgaltcfhLSiAQdQLBMzm8prBm5kYR7ewBJJVtgWy5bAC8IYkYQg6O4U-OpWToFGwc+l8dhZ2ZHhSE2cWAAH4HvIzM0tAkDECjFwumCLEofv0HAkrtCmGibgA1WGmJoIpH4lq6Zy5ZGOIA