Typed Source: Autocompletion for standard source functions does not work

[sayomaki]

Currently, code auto-completion for all of the standard library functions do not work when in Source Typed mode. The expected list of functions that should appear can be found in these links:

https://docs.sourceacademy.org/source_1/

Expected Behaviour:

The auto-completion should show the built in functions when you start typing as follows:

Actual Behaviour:

There is no auto-completion for the built in functions in Source Typed.