* Rename JS concepts
1. Assignment declaration -- an assignment that is treated like a
declaration. Previously called [JS] special (assignment|declaration),
among other things.
2. Expando -- a value that can be used as a target in assignment
declarations. Currently, a class, function or empty object literal.
Functions are allowed in Typescript, too. Previously called a JS
container, JS initializer or expando object.
3. JavaScript -> Javascript. This is annoying to type, and looks like
'Java Script' in a camelCase world.
Everything is a pure rename as far as I know. The only test change is
the API baselines, which reflect the rename from SymbolFlags.JSContainer
to SymbolFlags.Assignment.
* Remove TODO
* Rename Javascript->JS
Note that this introduces a variable name collision in a couple of
places, which I resolved like this:
```ts
const isInJavascript = isInJSFile(node);
```
* Add 'move to new file' refactor
* Code review, and support commonjs
* Compute movedSymbols completely before using, and support `export import`
* Fix assertion error: sort empty change before non-empty change
* Remove extra newline
* Add allowTextChangesInNewFiles preference
* Add the new file to 'files' in tsconfig
* Avoid parameter initializer
* Update API baselines
* Use path relative to tsconfig.json
* Code review
* Fix error where node in tsconfig file was missing a source file
