Provide context for the use of the word "component" in the definition of "label"

[mbgower]

Addresses some of the points in #4252 by clarifying if the use of "component" is used as a synonym for the defined term User Interface Component in the definition of label, which reads:

text or other component with a text alternative that is presented to a user to identify a component within web content

This is particularly in light of the fact label is used normatively in Headings and Labels.

On consideration, it will likely make sense to either make the definition link to UIC (a normative change) or add in a note that it is not meant as a synonym for UIC.