Update american-journal-of-archaeology.csl

1) Removes comma which appears after "edited by" but before first editor's name.
2) Removes whitespace between semicolon and page numbers for journal articles.
since we're editing this anyway, let's do it properly and get rid of the hard-coded text value="edited by" and use
```<label form="verb" suffix=" "/>``` (analogous to the secondary contributors macro).
You can also take out the whole test for author, that's taken care of by the substitute function in the contributor macro.