Try to expose more API-functionality in the TypeScript definitions
Try to expose more API-functionality in the TypeScript definitions

While these types apparently makes sense in TypeScript environments, we really don't want to extend the *public* API by simply exporting the relevant classes directly in `src/pdf.js` (since they should never be called/initialized manually).

Please see e.g. issue 12384 where this was first requested, and note that a possible work-around was also provided there. This patch simply implements that work-around[1], which will hopefully be helpful to TypeScript users.

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[1] Based on the discussion in PR 13957, the two previous patches appear to be necessary for this to actually work.

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