Fix minor nits in README.md

[bollu]

• Make the quotes render using blockquotes
• Fix some headings that were not bolded due to being written like ##this instead of like ## this

Lovely library, thanks for writing it! :D

[waldyrious]

Shouldn't the quote author names be outside the quoted blocks?

Or at least there should be a blank line between each quote and its author, so that the line breaks present in the previous formatting are preserved.

[bollu]

@waldyrious fixed!

[wolftype]

Thanks for the fixup!