Clarify usage of the components indexer [SPR-15793] #20348
The new components indexer introduced in Spring Framework 5 is an alternative to classpath scanning for large projects and our documentation does not clearly state it so.
There's nothing wrong adding the indexer in a small project but the gain is almost invisible so we should improve our doc to provide a bit more guidance.
See also this thread
Affects: 5.0 RC2
Referenced from: commits 19c88f2