help: add "internals" topic
We introduce the "internals" help topic, which renders an index of
available sub-topics. The sub-topics themselves are still not
reachable via the help system.
fixbundle() {
grep -v 'saving bundle' | grep -v 'saved backup' | \
grep -v added | grep -v adding | \
grep -v "unable to find 'e' for patching" | \
grep -v "e: No such file or directory" | \
cat
}