doc/INSTALL does not mention ENABLE_T3_TEST_SUITE to run tests

[ergodicbreak]

hi, in doc/INSTALL it says

-DENABLE_T3_DEBUG=<YES|NO> (default is NO)

Will build the debug version of the T3VM. This results in slower code, but
is useful for people who want to make changes to the source code. This will
also enable the TADS 3 test suite.

and

If you used -DENABLE_T3_DEBUG=YES, you can run the test suite with:

ctest

However the build wasn't creating a test target until I found the flag ENABLE_T3_TEST_SUITE, setting that on ran the tests. Does doc/INSTALL need updating here?