Typo in tabular-metadata §4 (encoutered)

[mgoodhand]

Typo in https://www.w3.org/TR/2015/REC-tabular-metadata-20151217/#annotating-tables

Compliant applications must ignore properties (aside from common properties) which are not defined in this specification and must generate a warning when they are encoutered.

s/encoutered/encountered/

[iherman]

Thanks @mgoodhand, I have added this to the official errata for the standards.