fix broken markdown

Author: Sam Stokes

Diff for: README.markdown

@@ -47,7 +47,7 @@ To use in your `pom.xml`:
 
 ## Caveats ##
 
-`SimpleJSONSerializer` will only *de*serialise JSON objects, arrays, or `null`;
+`SimpleJSONSerializer` will only deserialise JSON objects, arrays, or `null`;
 it will not accept top-level strings or numbers (although of course strings and
 numbers *inside* arrays or objects are fine).