Remove unnecessary blank line in GapElement_Function for cleaner code

Author: cxzhong

src/sage/libs/gap/element.pyx

@@ -2495,7 +2495,7 @@ cdef class GapElement_Function(GapElement):
             ....:         print('because Sum needs a list as argument')
             ....:     except ValueError:
             ....:         pass
-            
+
             sage: libgap_exec = libgap.eval("Exec")
             sage: libgap_exec('echo hello from the shell')
             hello from the shell