Return completions for properties with string keys

[mjbvz]

From microsoft/vscode#36429

Code

const sounds = {
    'cat': 'meow',
    'd o g': 'woof', 
    '🐮': 'moo'
};

sounds.

Trigger completions at the end of sounds

Expected behavior:
Completion entries for all three member properties are returned. Selecting each triggers the following insertions:

sounds.cat
sounds['d o g']
sounds['🐮']

Actual behavior:
Only completion entries for valid JS identifier names are returned (cat in this instance).

The object in this case already has the correct types, we just don't return completions for them

[mjbvz]

This would likely require adding a new insertText property on CompletionEntry

interface CompletionEntry {
    name: string;

    insertText?: string

    ...
}