Bad formatting for codefix to change extends to implements

TypeScript Version: nightly (2.6.0-dev.20170927)

See the fourslash test codeFixChangeExtendsToImplementsAbstractModifier.ts and codeFixChangeExtendsToImplementsWithDecorator.ts.

Code

abstract class A extends I1 implements I2 { }

Expected behavior:

abstract class A implements I1, I2 { }

Actual behavior:

abstract class A implements I1 , I2 { }

[amcasey]

When fixing this, be careful not to break abstract class A extends I1 /*hello*/ implements I2 { }.

[amcasey]

The comma is inserted as a direct replacement for the implements keyword. This results in a related problem:

abstract class A
    extends I1 // hello
    implements I2 { }

becomes

abstract class A
    extends I1 // hello
    , I2 { }

Presumably, the desired outcome is actually

abstract class A
    extends I1, // hello
    I2 { }

[amcasey]

More generally,

interface I1 { }
interface I2 { }

class MyClass /*A*/ //B
    /*C*/ extends /*D*/ I1 /*E*/ //F
    /*G*/ implements /*H*/ I2 /*I*/ //J
{
}

should probably become

interface I1 { }
interface I2 { }

class MyClass /*A*/ //B
    /*C*/ implements /*D*/ I1, /*E*/ //F
    /*G*/ /*H*/ I2 /*I*/ //J
{
}