Unused or unnecessary code.
Diagnostics with this tag are rendered faded out. The amount of fading
is controlled by the "editorUnnecessaryCode.opacity" theme color. For
example, "editorUnnecessaryCode.opacity": "#000000c0" will render the
code with 75% opacity. For high contrast themes, use the
"editorUnnecessaryCode.border" theme color to underline unnecessary code
instead of fading it out.
Deprecated or obsolete code.
Diagnostics with this tag are rendered with a strike through.
Additional metadata about the type of a diagnostic.