Pie: showData
`pie showData` adds each slice's value to its legend row, printed as written.
pie-showdata.mmd
pie showData title Key elements in Product X
"Calcium" : 42.96
"Potassium" : 50.05
"Magnesium" : 10.01
"Iron" : 5pie showData title Key elements in Product X
"Calcium" : 42.96
"Potassium" : 50.05
"Magnesium" : 10.01
"Iron" : 5