Fix "end of file while inside a group" error in NDK

Add the missing end of group markers to the files
which generate the "end of file while inside a group"
warning.

Bug: 183024041
Test: development/tools/ndk/build_ndk_docs.py 2>&1 \
         | grep "end of file while inside a group"
Change-Id: Ib41840bbc72651ad90aaac878d36c233b5284cf3
3 files changed