History of Math.round()

Add "Return value" section as per Bug 1287421

Adding a simpler alternative than Decimal rounding that others can use. This adds the ability to specify precision when rounding.

bring back decimal rounding exmaple that was here in earlier revisions

Adding link to the decimal rounding code that have been moved to github because many webpages like stackoverflow link to this page saying "it is better to use the code examples in MDN <link>" when you search for decimal rounding in javascript

correct description: absolute value is the result of the Math.abs() function, but -3.5 is roundet to -3 and not to -4

simplification

minuscules

rectification (description was valid only for a nonnegative argument)