Reddit cofounders Steve Huffman and Alexis Ohanian spent about eight straight years living together, initially as college roommates, playing World of Warcraft late into the night and later working together on the foundations of the discussion forums service now frequented by nearly 270 million people. But that history was missing from Reddit’s sales pitch to investors published Thursday announcing its plans to go public on the New York Stock Exchange: Reddit’s filing with the US Securities and E...