JS: Expand cheat sheet page

[asgerf]

Expands the JS data flow cheat sheet with:

• SourceNode.getALocalUse
• AccessPath module
• Elaborate on RemoteFlowSource and move into its own section.

cc @lcartey @rvermeulen, let me know if you have any input of this.

[rvermeulen]

Thanks for updating the cheat sheet!

Might it be useful to reference the RemoteFlowSource part in the cheat sheet in the following paragraph found at https://codeql.github.com/docs/codeql-language-guides/specifying-additional-remote-flow-sources-for-javascript/ or otherwise add emphasize on the isUserControlledObject predicate?

To model a new source of untrusted input, such as a previously unmodelled library API, you can define a subclass of RemoteFlowSource that covers all uses of that API. All standard analyses will then automatically pick up this new source of remote flow.

[erik-krogh]

LGTM 👍