Add improvements to package documentation #7936

Job	Run time
Build Ballerina Lang	7m 1s
Build Ballerina Distribution	41m 47s
Build Stdlib Level (1)	3m 40s
Build Stdlib Level (2)	12m 38s
Build Stdlib Level (3)	6m 4s
Build Stdlib Level (4)	15m 20s
Build Stdlib Level (6)	18m 32s
Build Stdlib Level (5)	26m 28s
Build Stdlib Level (7)	29m 4s
Build Stdlib Level (8)	28m 33s
Build Stdlib Level (9)	3m 11s
	3h 12m 18s

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