Replace contentShorthand with itemShorthand

[bmdalex]

Replace contentShorthand with itemShorthand

Steps

We have a bug in our components propTypes for the content slot. Most of our components use the Slot component to generate their content slot, meaning that the propTypes for content prop should be:

Expected Result

content: customPropTypes.itemShorthand

Actual Result

content: customPropTypes.contentShorthand

Solution

• go to all components and verify their propTypes for the slots are correct;
• for all component slots created with Slot component, replace customPropTypes.contentShorthand propType for that slot with customPropTypes.itemShorthand
• check in docs examples that warnings such as the one below don't appear anymore (for instance when providing an object as a slot value):

<Button content={{ content: "Click here" }} />

will generate the following warning:

[bmdalex]

fixed by #528