Fix incorrect <input> type for Date Picker example

[solkaz]

Proposed changes

Fix the documentation for Date Picker; it requires type="text", but it was set to type="date" in the example (the actual component had the correct type).

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to change).

Checklist:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.