Display "review" results as warnings

When a result has kind equal to "review", the extension displays it as "informational". But in fact, a "review" result should be displayed as "warning", because it means that it's an issue that requires human review to determine if there's actually a problem.

The guidance for viewers is:

• Errors: results that break/block processes.
• Warnings: items actively tracked that should always display to users but not block anything.
• Informational: low-importance items that do not display by default.

Here is how the viewer should treat results with a kind value other than "fail":

[1] Because this value means that the tool didn't have enough information to know if there was a problem. This is used by program correctness provers. If a prover doesn't know (for example), if a particular function can throw an exception, it might not be able to decide whether a code path is safe.

[2] But I think the web viewer already shows a green check-mark for a "pass" results, right? This is good.

@michaelcfanning FYI

Start in the viewer code that maps SARIF result kind values to displayed severities. Verify the existing treatments for notApplicable, open, pass, and fail, then make review display as a warning and confirm the viewer reflects the requested table.