Merge pull request jgm#411 from dfc/patch-1

"be is in" -> "be in"

README

@@ -442,7 +442,7 @@ Options affecting specific writers
     By default, pandoc will include the following metadata elements:
     `<dc:title>` (from the document title), `<dc:creator>` (from the
     document authors), `<dc:date>` (from the document date, which should
-    be is in [ISO 8601 format]), `<dc:language>` (from the `lang`
+    be in [ISO 8601 format]), `<dc:language>` (from the `lang`
     variable, or, if is not set, the locale), and `<dc:identifier
     id="BookId">` (a randomly generated UUID). Any of these may be
     overridden by elements in the metadata file.