Remove outdated warning in docs

[LilithHafner]

I'm assuming that these restrictions are fixed now that the PR has merged, but I don't know for sure.
Closes #637

[coveralls]

Pull Request Test Coverage Report for Build 2789839894

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.3%) to 64.334%

---

Totals
Change from base Build 2758684380:	-0.3%
Covered Lines:	1434
Relevant Lines:	2229

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💛 - Coveralls

[codecov]

Codecov Report

Merging #654 (c73414c) into master (ac0ec81) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #654   +/-   ##
=======================================
  Coverage   65.60%   65.60%           
=======================================
  Files          32       32           
  Lines        2721     2721           
=======================================
  Hits         1785     1785           
  Misses        936      936           

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