[CX] Invalid infinity value in DP3 documentation

DP3 documentation has incorrect example of infinity double values in

http://docs.couchbase.com/prerelease/analytics-dp3/9_data_type.html

It says for DOUBLE/FLOAT types:

• Example:
  {{ { "v1": double("NaN"), "v2": double("INF"), "v3": double("-INF"), "v4": "-2013.593823748327284" }; }}
• The expected result is:
  {{ { "v1": "NaN", "v2": "Infinity", "v3": "-Infinity", "v4": -2013.5938237483274 }}}

However we serialize INF/-INF as INF/-INF, instead of Infitity/-Infinity. It was changed by https://issues.apache.org/jira/browse/ASTERIXDB-2000