Add sidebar expand and collapse icons

[colebemis]

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[ashygee]

@colebemis is collapse and expand the correct descriptor for this? not open/close?

[colebemis]

@ashygee I'm fine with either.

[colebemis]

expand/collapse feel like they represent the action of "expanding" or "collapsing" which is how the icons will be used. open/close feel more like they could be states of the sidebar.

[ashygee]

expand/collapse feel like they represent the action of "expanding" or "collapsing" which is how the icons will be used. open/close feel more like they could be states of the sidebar.

This makes perfect sense. let's keep as is then! 🚀 it!