chore: fix grammatical errors and update layout

[marcnjaramillo]

Problem

There are several grammatical errors throughout the docs, and the layout is not consistent in some places. For example, some of the alert boxes have custom titles while others don't.

What this PR does

• Resolves grammatical errors
• Updates alert boxes that previously had no titles
• Adds additional alert boxes
• Updates section on selecting devnet along with an image showing the toggle button
• Updates the date format in Community NFT DAO to align with ISO 8601 specification