Simplify User.display_name a bit.
Simplify User.display_name a bit.

rapptz/discord.py,mgardne8/discord.py,imayhaveborkedit/discord.py,Harmon758/discord.py,Theoretical/UselessBot,khazhyk/discord.py,jhgg/discord.py,Rapptz/discord.py,variablehair/Eggplantato,Harmon758/discord.py,lgkern/PriestPy