Update example for %alias_magic (#14276)

Fix example for creating `%alias_magic`

IPython/core/magics/basic.py

@@ -124,7 +124,7 b' class BasicMagics(Magics):'
           In [6]: %whereami
           Out[6]: '/home/testuser'
 
-          In [7]: %alias_magic h history "-p -l 30" --line
+          In [7]: %alias_magic h history -p "-l 30" --line
           Created `%h` as an alias for `%history -l 30`.
         """