Use "Condition" prefix for conditions in make-doc
Rearrange code in make-doc.lisp
Move package name from command line to make-doc.lisp
Move api-doc first-level heading to make-doc.lisp
Remove api-doc.md from the clean target

The file is in the repository and shouldn't be deleted in any case.
Adjust the header line of enchant.lisp
Fix typo in the doc string of DICT
Remove unnecessary "doc" target from Makefile