Embedded JavaScript Support Enhancements

[neomantra]

go-echarts is a cool blend of Golang, JSON, and JavaScript. As noted in this PR, in addition to string fragments one can also go:embed JavaScript files.

These embedded JavaScript function strings have certain requirements:

• they must be quoted with single-quotes ' and not double-quotes ""
• they also cannot contain comments.

Here's a TODO list in this realm:

• improve documentation on restrictions on JavaScript function embedding
• improve documentation on go:embed
• typescript workflow example? should be able to match eCharts typings
• add Golang simple linter function to pre-flight check JavaScript files
• add simple linting script which can validate files
• add a comment-stripping function (WIP in NM Various Enhancements #285)