PHILADELPHIA – Makai Lemon’s last name is not conducive to positive connotations, unless your over 21 and partial to Lemon Drop shots, or a teenager fond of Lemonhead candy. Usually, a lemon is something sour or a bad automobile purchase. The receiver the Eagles moved up three spots to take at No. 20 overall on Thursday night could end being a very sweet pick, certainly not the lemon that was Jalen Reagor when the Eagles picked him in the first round six years ago. Granted, Reagor set a low bar, playing only 28 games in his two years with the Eagles and catching just 64 passes. Lemon might have 64 catches as a rookie. He’s that good. There doesn’t seem to be any special trait he possesses – not size (he’s 5-11) or speed (he was clocked in the 4-8-5.3 range at USC’s pro day in March). “It’s just the mentality and the heart you play with,” said Lemon, when he was introduced to the media on Friday evening.…