feat: allow the autocompletion of a linked data value

[janechu]

Description

This change allows the autocompletion on the input of the linked data control in the <Form />.
Now, when Tab is pressed the value will autocomplete if there is a single matching item in the linked data list. If Enter is pressed the current value will be evaluated against lazily (lowercase values) or strictly (exact value) and if a single match can be found using either of these methods then the value will be added.

An example of where this helps:

Example 1: The list of supplied linked data includes:

[
    "Foo",
    "foo"
]

When "foo" is typed, it will match "Foo" and "foo" in the dropdown, however if enter is pressed then it will match "foo" exactly and add this value.

Example 2: the list of supplied linked data includes:

[
    "foo-Bar",
    "foo",
]

When "foo-bar" is typed it will match "foo-Bar" lazily and when enter is pressed it will add the linked data.
Likewise if "foo-" is typed and then Tab is pressed, it will autocomplete to "foo-Bar" and the next enter is pressed it will add the linked data.

Issue type checklist

• Chore: A change that does not impact distributed packages.
• Bug fix: A change that fixes an issue, link to the issue above.
• New feature: A change that adds functionality.

Is this a breaking change?

• This change causes current functionality to break.

Adding or modifying component(s) in @microsoft/fast-components checklist

• I have added a new component
• I have modified an existing component
• I have updated the definition file
• I have updated the configuration file

Process & policy checklist

• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.