This makes them available for use by other language servers.
Also as a bonus, update the Shell language server to discover some
symbols and add go-to-definition functionality :^)
The C++ LanguageServer can now find the matching declaration for
variable names, function calls, struct/class types and properties.
When clicking on one of the above with Ctrl pressed, HackStudio will
ask the language server to find a matching declaration, and navigate
to the result in the Editor. :^)
