[graph-tool] Probably copy-paste typo

Hello. Nothing special, but I found probably copy-paste misprint in documentation: https://graph-tool.skewed.de/static/doc/draw.html#graph_tool.draw.graph_draw *vprops* : dict (optional, default: None) Dictionary with the vertex properties. Individual properties may also be given via the vertex_<prop-name> parameters, where <prop-name> is the name of the property. *eprops* : dict (optional, default: None) Dictionary with the *vertex* properties. Individual properties may also be given via the edge_<prop-name> parameters, where <prop-name> is the name of the property.