Correct keyword used by source hash commands

gprMax/hash_cmds_multiuse.py

@@ -122,7 +122,7 @@ def process_multicmds(multicmds):
                     p1=(float(tmp[1]), float(tmp[2]), float(tmp[3])),
                     waveform_id=tmp[4],
                     start=float(tmp[5]),
-                    end=float(tmp[6]),
+                    stop=float(tmp[6]),
                 )
             else:
                 logger.exception(
@@ -158,7 +158,7 @@ def process_multicmds(multicmds):
                     p1=(float(tmp[1]), float(tmp[2]), float(tmp[3])),
                     waveform_id=tmp[4],
                     start=float(tmp[5]),
-                    end=float(tmp[6]),
+                    stop=float(tmp[6]),
                 )
             else:
                 logger.exception(
@@ -192,7 +192,7 @@ def process_multicmds(multicmds):
                     resistance=float(tmp[4]),
                     waveform_id=tmp[5],
                     start=tmp[6],
-                    end=tmp[7],
+                    stop=tmp[7],
                 )
             else:
                 logger.exception(