Fixing issue with semicolons not being printed out for TSPropertySignature's

[ElonVolo]

Adds a fix to append a semicolon to the end of a TSPropertySignature statement.

export interface Test {
  A: string;
  R: string;
}

Without the fix, if I were to add a Typescript property named X with a string annotation it would print out as:

export interface Test {
  A: string;
  R: string;
  X: string
}

[ElonVolo]

@coderaiser, can you take a look at this when you get a chance (I know thing's are probably a mess on your side of the world right now).

[coderaiser]

This is very good! Could you please add a test for this.

A mess is big, but coding helps not think about it.