Fix typo from "to" to "do"

Signed-off-by: Aristo Chen <aristo.chen@canonical.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>

Fixed a variable that was incorrect during the calculation of fileblks.

Signed-off-by: Ken Kurematsu <k.kurematsu@nskint.co.jp>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>

Linux internally uses https://www.kernel.org/doc/html/latest/ for
documentation links. When referring to their documentation we should do the
same.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

Explain block maps by going through two common use-cases.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Simon Glass <sjg@chromium.org>