Update docs/InteractiveForceGraph.md

[RosaRomeroGomez]

Added note to docs/InteractiveForceGraph.md related to render issue discussed on #60 and suggested by @kristianmandrup.

[CLAassistant]

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[coveralls]

Coverage remained the same at 74.932% when pulling 7c9cbd2216e4f39ea916b7609ecfdaa92a0a7d05 on RosaRomeroGomez:update-README-alpha-option into 88f0141c39a32545db229296498c1da26e682422 on uber:master.

[kristianmandrup]

Thanks a lot. Will take a look shortly :)