Fix ndk native reference documentation link errors/warnings

Trivial changes, no functionality impact.

Bug: 183002717
Test: build ndk with 'm ndk' works
Change-Id: I1ee646f28500ad5769abdddd4e9780a1915fd528
(cherry picked from commit 7fed43d17aa7c6d8ff4d7a179d53ee7dc9f26d89)
5 files changed