fix: restore and polish various styling regression

[hristototov]

Addressed the following styling issues:

• for codeblocks, previously it was no border, but now it is has border - not sure if intentional
• there is now a edit button in the sidebar which looks broken (2 icons, no spacing before marketing copy), there is also an edit button at the bottom so another one seems unexpected
• the right border on active items in the sidebar is gone, not sure if it's intentional. also seems there is no spacing between sidebar items now
• probably a bug in the theme itself, if i click the "Next page"/"Previous page" buttons at the bottom, it keeps its active styling even on the next page
• the # link that you get before the heading when you hover it now has an underline when you hover the # - seems unintentional
• the TOC on the right side don't have proper padding to show heading level like before
• previously external links had this arrow after them, but now it's gone
• the padding around the copy and wrap buttons on the codeblocks changed - previously they looked centered for single line codeblocks, but now they don't

Screenshots before and after the fixes

4-clear-active.state.mov

[github-actions]

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[artus9033]

LGTM, great job!

[satya164]

This one looks wrong

it should be like this (no gap between the 2 lines)