docs: byline and licenses for the 3.13.0 post

- author and date below the title, styled as .nj-byline; its link gets
  no external-link icon
- the license of every library in the thanks section, checked against
  each project's license files; credit sonic-rs for QUOTE_TAB, which
  orjson adapted from it

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/css/brand.css

@@ -759,6 +759,11 @@ body:has(.nj-hero) .md-content {
     }
 }
 
+/* blog posts: author and date right below the title */
+.md-typeset .nj-byline { margin: -.8rem 0 1.6rem; font-size: .75rem; color: var(--md-default-fg-color--light); }
+.md-typeset .nj-byline a { color: inherit; }
+.md-typeset .nj-byline a:hover { color: var(--md-accent-fg-color); }
+
 /* figure captions: "Figure N." in bold, close to the figure, set in from the text column; figures and tables are
    numbered per page, each with its own counter */
 .md-content__inner { counter-reset: nj-figure nj-table; }