Improve incl_same_name

[fantazio]

The examples/docs/exported_values/incl_same_name was only testing a simple case, corresponding to #55 (with Oo instead of List).

This PR extends the test to more cases:

• whether the original module has an mli or not,
• whether the new module does (using include module type of if it does),
• and the very corner case of the new module exporting the same value as the original one and at the same location.

The use of Oo is now redundant. Thus, it is removed.
The to_incl subdirectory contains the "original" modules, with and without .mli. The incl_{with|without}_intf define new modules, with and without .mli, which include and are name the same as the original ones.

If we look more closely into the results by using -E calls:1, the calls sites for values used once are also confused:

.>->  ALMOST UNUSED EXPORTED VALUES: Called 1 time(s):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/with_intf.mli:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:2:2

./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/with_intf.mli:5: redefined_used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:2:2

./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/without_intf.ml:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:3:2

./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/without_intf.mli:5: redefined_used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:3:2


./examples/docs/exported_values/limitations/incl_same_name/incl_without_intf/with_intf.ml:5: redefined_used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:2:2

./examples/docs/exported_values/limitations/incl_same_name/incl_without_intf/with_intf.mli:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:2:2

./examples/docs/exported_values/limitations/incl_same_name/incl_without_intf/without_intf.ml:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:3:2

./examples/docs/exported_values/limitations/incl_same_name/incl_without_intf/without_intf.ml:5: redefined_used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:3:2


./examples/docs/exported_values/limitations/incl_same_name/to_incl/with_intf.mli:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:2:2

./examples/docs/exported_values/limitations/incl_same_name/to_incl/without_intf.ml:3: used    Call sites:
./examples/docs/exported_values/limitations/incl_same_name/incl_with_intf/use.ml:3:2

--------

Se how all the call sites point to incl_with_intf/use.ml when some of them should point to to_incl/use.ml or incl_without_intf/use.ml