changelog: update changelogs to bugfix, not feature

NO_DOC=changelog
NO_TEST=changelog
NO_CHANGELOG=changelog

changelogs/unreleased/gh-6597-update-luarocks.md

-## feature/misc
+## bugfix/misc
 
-* Updated luarocks version to 3.9.2 (gh-6597).
+* Updated luarocks version to 3.9.2 to address rockspec security issues (gh-6587).

changelogs/unreleased/ghe-523-max-config-param-length.md

-## feature/box
+## bugfix/box
 
-* The maximum length of `box.cfg{}` string parameters is now 512 instead of 256.
+* The maximum length of `box.cfg{}` string parameters is now 512 to support a lengthy args, such as list of audit events (ghe-523).