[Docs Update] Explain "?" missing uploads

[Adal3n3]

Description

We heard customers ask what does "?" mean. https://docs.codecov.com/docs/coverage-percentages#what-is-%C3%B8

• Maybe add a screenshot that show "?" in the PR comment, and explain what they need to do to remove the "?"

Page(s)

Current State

[] Broken Link [] Unclear Language [] Inconsistent Formatting [] Missing Information [] Missing Updates for New Features [] Deprecated Features

Additional Information