Clean up sidebar

[alexkrolick]

These are mostly formatting changes except for condensing the Reason docs into one section.

• condense sidebar elements with only one child to a single nav entry
  • tweak nav alignment to account for subheadings so they are aligned the same as other elements
• add full titles for wrapper library docs
• condense reason docs and add more links back to language documentation
  • @wyze is this OK with you?
• fix some broken/wonky layout items
  • vertically center the octopii 🐙 😄
  • broken svg
  • lighten link color
  • use 3 instead of 4 columns for the ecosystem logos since there are 6

[wyze]

I'm okay with the layout structure. I had one comment about the example that was brought to my attention yesterday in a PR.