Tweak "Typical sources and deps modifications" section.
Tweak "Typical sources and deps modifications" section.

The current example, while a literal translation of the gyp version, is
misleading people: https://codereview.chromium.org/1906283002/#msg7

BUG=none

Review URL: https://codereview.chromium.org/1904383002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#389077}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk