[BUGFIX] unicode comma fix

[liuzh47]

Description

There is a unicode comma in the print statement. It needed to be replaced with an ASCII comma.

Fixes #1055

Checklist

Essentials

• PR's title starts with a category (e.g. [BUGFIX], [MODEL], [TUTORIAL], [FEATURE], [DOC], etc)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented

cc @dmlc/gluon-nlp-team

[codecov]

Codecov Report

Merging #1056 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1056   +/-   ##
=======================================
  Coverage   88.27%   88.27%           
=======================================
  Files          67       67           
  Lines        6252     6252           
=======================================
  Hits         5519     5519           
  Misses        733      733

[mli]

Job PR-1056/1 is complete.
Docs are uploaded to http://gluon-nlp-staging.s3-accelerate.dualstack.amazonaws.com/PR-1056/1/index.html

[leezu]

CI will fail until #1058 as the mxnet version used prior to #1058 suffers from apache/mxnet#16193

[mli]

Job PR-1056/2 is complete.
Docs are uploaded to http://gluon-nlp-staging.s3-accelerate.dualstack.amazonaws.com/PR-1056/2/index.html