Improve some error messages.

It's rude not to say _what_ you couldn't understand, and it's confusing
not to _quote_ what you couldn't understand.

Bug: https://issuetracker.google.com/286968214
Test: adb logcat --pid ''
Change-Id: Ifa04f8c64cacc4734d24291eebf0dff3a5c4b941
1 file changed
tree: d7de3718feebdbaea5dc2b8a33e9195adaa8f512
  1. liblog/
  2. logcat/
  3. logd/
  4. logwrapper/
  5. rust/
  6. OWNERS
  7. PREUPLOAD.cfg
  8. TEST_MAPPING