[Documentation] Graphics properties can be supplemented with documentation for function configuration

[xuefei1313]

Documentation Title or Section

https://visactor.com/vchart/option/barChart#bar.style.fillOpacity

Issue Description or Suggestion

add function tag to show it could be set as function

[shiquda]

Can you assign this issue to me?

[xuefei1313]

这里需要给可以支持函数的属性都补充对应的tag
以 label 为例。系列的label，totalLabel的样式里可以每一个属性写函数，
但是在轴的 label 里，label.style 支持函数， label.style.fill. 不支持函数。