HaikuBook: minor fixes

Fix some copy-pasta and strange grammar.
Remove a note that seems unnecessary in context and easy to misinterpret
out of context.

Change-Id: If1ce26b293c8098c260a9697fb0ef0611a4958c4
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7358
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>

BListView: Add ScrollTo(index) method, auto-scroll on drag

Multi-select lists may also auto-scroll on drag now as well.

Document ScrollTo(index). Give Scrolling its own section.

Change-Id: I36284a28376a01bafd23ddb30162fc786fb41521
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7213
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

API docs: it's => its fix

IK documentation update

* Add \since directive to each method.
* Add documentation for BScrollBar and BScrollView classes.
* Title Case group titles.
* Some other minor documentation updates.

Docs: Put a comma in Haiku, Inc. in the copyright.

Minor updates to BListView docs

Fix rest of warnings, doxygen now runs cleanly.

The BTextView::SetText() methods were included twice, update the first and
remove the second.

Add documentation for BListView and BListItem classes

IK documentation update

* Add \since directive to each method.
* Add documentation for BScrollBar and BScrollView classes.
* Title Case group titles.
* Some other minor documentation updates.

Docs: Put a comma in Haiku, Inc. in the copyright.

Minor updates to BListView docs

Fix rest of warnings, doxygen now runs cleanly.

The BTextView::SetText() methods were included twice, update the first and
remove the second.

Add documentation for BListView and BListItem classes