Edit "Where to put my code" on docs/style.md about how to refer the style files

[luixxiul]

Description

Edit "Where to put my code" on docs/style.md about how to refer the style files.

See: f0c77b7#r144715080 on app/renderer/components/tabs/content/closeTabIcon.js

// Styles
const {theme} = require('../../styles/theme')
-const {spacing, zindex} = require('../../styles/global')
-const {opacityIncreaseKeyframes} = require('../../styles/animations')
+const globalStyles = require('../../styles/global')

Before introducing a new way of referring the styles, let's edit docs/style.md#where-to-put-my-code to explain to do so (and why we do so).

@cezaraugusto: I am not quite sure yet why this is needed, but maybe for readability (and slight performance improvement)?

Additional Information