API spec: fix a typo, use complete XML
API spec: fix a typo, use complete XML

  - The "it" description had a typo
  - This failed on JRuby, before adding the closing XML tag
  - This was repaired in passing, by stenlarsson, thanks!

Co-authored-by: Sten Larsson <69ff9566b992c2a90553cb98d32afb265a308c3e@burtcorp.com>

savonrb/nori