fix jsdoc for expand. closes #194

Author: ctalkington

lib/core.js

@@ -532,7 +532,7 @@ Archiver.prototype.append = function(source, data) {
  * and {@link TarEntryData}.
  * @param  {(String|Array)} mappings[].src Pattern(s) to match, relative to the `cwd`.
  * @param  {String} mappings[].dest Destination path prefix.
- * @param  {String} mappings[].expand Process a dynamic src-dest file mapping.
+ * @param  {Boolean} mappings[].expand Process a dynamic src-dest file mapping.
  * @param  {String} mappings[].cwd All `src` matches are relative to (but don't include)
  * this path. requires `expand`.
  * @param  {String} mappings[].ext Replace any existing extension with this value in