[Include analysis] Add "Direct Includes" field and filter

This allows seeing what headers are included by a certain file, which
can be useful for checking which are the large includes in a file.
(It needs https://reviews.llvm.org/D100480 for correct data.)

This CL also moves the legend into tooltips on the column headers,
as well as some wording tweaks.

Bug: 1192087
Change-Id: Ia50dfb154125df0dd23bc84bd9022468b8bac26a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2831293
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#873294}
GitOrigin-RevId: 7e122bdad11bb1b6f1d209fe92b92897256a3d16
1 file changed