* docs: Update Quick Start Guide for Electron 12
With `contextIsolation` enabled by default in Electron 12, the Getting Started Guide no longer works as it is written. In order for the basic example to display values from `process.versions`, we need to add a `preload.js` to the example.
* fix: annotate preload code block with a language
* docs: update quick-start Fiddle example to use preload to provide version info
* fix: ensure example files end in a newline
* docs: add security warning to instructions for turning off contextIsolation
Co-authored-by: John Kleinschmidt <jkleinsc@github.com>
* docs: treat preload as an adjective instead of a noun
Co-authored-by: John Kleinschmidt <jkleinsc@github.com>
Co-authored-by: John Kleinschmidt <jkleinsc@github.com>
