[SPARK-24899][SQL][DOC] Add example of monotonically_increasing_id standard function to scaladoc#21858

jaceklaskowski wants to merge 1 commit intoapache:masterapache/spark:masterfrom

jaceklaskowski:SPARK-24899-monotonically_increasing_idjaceklaskowski/spark:SPARK-24899-monotonically_increasing_idCopy head branch name to clipboard