Geometry of binding of the benzamidine‐ and arginine‐based inhibitors Nα‐(2‐naphthyl‐sulphonyl‐glycyl)‐dl‐p‐amidinophenylalanyl‐piperidine (NAPAP) and (2R,4R)‐4‐methyl‐1‐[Nα‐(3‐methyl‐1,2,3,4‐tetrahydro‐8‐quinolinesulphonyl)‐l‐arginyl]‐2‐piperidine carboxylic acid (MQPA) to human α‐thrombin