Improve annotations and docs for PublicPromise
Improve annotations and docs for PublicPromise

During docs review, I noticed that resolve and reject on PublicPromise
were documented as fields rather than as methods.  This redefines the
types of resolve and reject so that they show up as proper methods.

Issue #1259

Change-Id: I0b7e22f9f1edf7d8ba15362306c55d7cdbd32e76

tvoli/shaka-player,vimond/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,vimond/shaka-player,shaka-project/shaka-player,vimond/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player