[Docs] Principles updates

[aweell]

Epic description

Tasks

• [Principles] Update overview page #527
• [Principles] Update component spacing tokens #611
• [Typo] Update font-leading-loose-01 value #624
• [Color] Transparent neutral scale with alpha values #629
• [Typo] Updates on typography documentation #636

[aweell]

Closed via #625, #630, #639, #640, #555 and #616