fix: extract text from tiptap bodies, and read the right description field (#4)v0.3.3

Checking the library against the live API disproved what its comments
claimed. Comment and Description were handing back raw JSON blobs, and
the parser this package has always carried could not have prevented it.

DeviantArt no longer stores rich text as Draft.js. It uses tiptap:

  Draft.js, what we parse:  {"blocks":[{"text":"..."}]}
  tiptap, what DA sends:    {"version":1,"document":{"type":"doc",...}}

Across 34 live comments: 33 tiptap, 0 Draft.js, and 33 whose .Comment was
the raw JSON. flattenMarkup now walks the tiptap tree — text nodes joined
per block, hardBreak as a newline, entities decoded — and keeps the
Draft.js path for old bodies that still carry it. Nodes with no text of
their own (images, galleries, emotes) drop out, as they always did.

The description had a second, larger bug behind that one. It lives in
Extended.DescriptionText, not TextContent, which GetDeviation read: of 24
deviations sampled, 23 populated the former and 1 the latter. So
Post.Description was empty for nearly every deviation, and the txt[1]
guard removed in 3dad0ea was never what stood in the way. Prefer
Extended.DescriptionText and fall back, since either may be the one set.

Verified against the live API rather than by reading: comments still raw
JSON went 33/34 to 0/34, and descriptions that were "" now return prose.

Also corrects the doc comments that asserted the Draft.js story on
pkg.go.dev, and notes that flattening drops images, links, and emotes.

0 files changed, 0 insertions, 0 deletions