Silence the Autoprefixer message being printed with all build logs
Silence the Autoprefixer message being printed with all build logs

The following is printed with every build, which gets kind of annoying when looking at the logs:
```
Replace Autoprefixer browsers option to Browserslist config.
Use browserslist key in package.json or .browserslistrc file.

Using browsers option cause some error. Browserslist config
can be used for Babel, Autoprefixer, postcss-normalize and other tools.

If you really need to use option, rename it to overrideBrowserslist.

Learn more at:
https://github.com/browserslist/browserslist#readme
https://twitter.com/browserslist
```

Given how we're using Autoprefixer, with a number of build-specific configs, simply changing the option name seems like the easiest solution here.

(I'm also adding a couple of newlines at the `autoprefixer` call-sites, to aid readability.)

caremerge/pdf.js,timvandermeij/pdf.js,xavier114fch/pdf.js,Snuffleupagus/pdf.js,mozilla/pdf.js,Shoobx/pdf.js,macroplant/pdf.js,showpad/mozilla-pdf.js,xavier114fch/pdf.js,Snuffleupagus/pdf.js,mozilla/pdf.js,nawawi/pdf.js,showpad/mozilla-pdf.js,timvandermeij/pdf.js,Shoobx/pdf.js,nawawi/pdf.js,mozilla/pdf.js,nawawi/pdf.js,caremerge/pdf.js,timvandermeij/pdf.js,Snuffleupagus/pdf.js,macroplant/pdf.js,macroplant/pdf.js,Shoobx/pdf.js,showpad/mozilla-pdf.js