flexWrap, alignContent, initialPlayground

Summary: Adds `initialPlayground` to the markdown header. Adds contents fro alignContent and flexWrap.

Reviewed By: emilsjolander

Differential Revision: D6987513

fbshipit-source-id: 41de309d427a9f42e09477170fb8512ce1e7a816

website/contents/properties/align-content.md

@@ -2,8 +2,12 @@
 path: "docs/align-content"
 title: "Align Content"
 hasPlayground: true
+initialPlayground: eyJ3aWR0aCI6NTAwLCJoZWlnaHQiOjUwMCwiZmxleFdyYXAiOjEsImNoaWxkcmVuIjpbe30se30se30se30se30se30se30se30se30se30se30se31dfQ==
 ---
 
 ## Align Content
 
+The property defines the distribution of lines along the cross-axis. This only
+has effect when items are wrapped to multiple lines (see [flexWrap](flex-wrap)).
+
 <controls prop="alignContent"></controls>

website/contents/properties/flex-wrap.md

@@ -2,8 +2,20 @@
 path: "docs/flex-wrap"
 title: "Flex Wrap"
 hasPlayground: true
+initialPlayground: eyJ3aWR0aCI6NTAwLCJoZWlnaHQiOjUwMCwiY2hpbGRyZW4iOlt7fSx7fSx7fSx7fSx7fSx7fSx7fSx7fV19
 ---
 
 ## Flex Wrap
 
+The `flexWrap` property is set on containers and controls what happens when
+children overflow the size of the container along the main axis. By default
+children are forced into a single line (which can shrink elements).
+
+If wrapping is allowed items are wrapped into multiple lines along the main
+axis if needed. `WRAP_REVERSE` behaves the same, but the order of the lines is
+reversed.
+
 <controls prop="flexWrap"></controls>
+
+When wrapping lines [alignContent](align-content) can be used to specify how the
+lines are placed in the container.