Fix Table class names in documentation

[jakemmarsh]

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Noticed these classes were improperly formatted in the docs when my styles weren't affecting anything and I did some DOM inspecting.

[codecov-io]

Codecov Report

Merging #1471 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #1471   +/-   ##
======================================
  Coverage    94.7%   94.7%           
======================================
  Files          47      47           
  Lines        1795    1795           
======================================
  Hits         1700    1700           
  Misses         95      95

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[wuweiweiwu]

nice catch!