Flow Explicit type specification for jsx

## Feature Request

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I have an issue when [...]
support syntax in flowtype plugin for type instantiation for jsx, eg:
```jsx
/>
```
according to: https://github.com/facebook/flow/issues/7672

**Describe the solution you'd like**
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**Describe alternatives you've considered**
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**Teachability, Documentation, Adoption, Migration Strategy**
If you can, explain how users will be able to use this and possibly write out a version the docs.
Maybe a screenshot or design?

The issue names no Babel files or tests. Start by reading the referenced Flow issue and locating Babel's Flowtype plugin and its JSX parsing tests. Done means the plugin accepts the shown explicit type syntax for JSX and the behavior is covered by tests.

Written by the indexing model from the issue text.