Documentation request: "Normal" phenotypes

[matentzn]

We need to document clearly the need for documenting "normal" phenotypes, and how they differ from "unqualified" phenotypes (i.e. OBA).

See quote from @sbello in slack:

The MP has a term branch for normal phenotype (MP:0002873) that has both no abnormal phenotype and phenotypic reversion. The branch has almost 4000 annotations. The distinction between the terms may be tricky to capture but it is worth discussing.

Please wrote a paragraph and that as a separate page to the documentation - this will also serve as a baseline to the paper.

Please also discuss the difference between the idea of "normal" and "unchanged", and "reverted", and how it related to the wildtype vs control discussion.