Change toc to use labicon

[marthacryan]

References

Fixes #8557.

Code changes

• Removes the icons from the style folder
• Adds icons that aren't already in ui-components
• Substitute code that uses css to add icons with code that uses imported icons from ui-components

User-facing changes

Here's the current ToC:

Here's the updated ToC:

Because there was already a markdown icon in ui-components, I used that icon instead of what was being used. Also, the "collapse" button is slightly smaller and a slightly lighter color. Otherwise, looks around the same.

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[marthacryan]

@kgryte How does this look to you? There were some icons that I removed without replacing them because I couldn't find where they were used ( such as the eyeball icons ) - I figured they had stopped being used at some point and been left in that folder, but if not I can add them to LabIcon too. Thanks!

[kgryte]

LGTM. Those icons predate my involvement with the ToC extension, so, if you could not find a use and everything looks the same, then deleting any extra icons seems fine to me.

[blink1073]

Thanks!