New refactoring: Convert Method Into Getter

[nicoespeon]

Discussed in #339

^{Originally posted by mick62 July 9, 2021}
Hi,

another useful (and needed) refactoring is the change from:

class A {
  getProp(): Y
     { return expr }
}
x = myA.getProp()

to

class A {
  get prop(): Y
     { return expr }
}
x = myA.prop

Btw. the counterpart 'setProp(val)' to 'set prop(val)'
might also be of interest although we use immutable objects most of the time.

Thank you in advance