Code Inspection: minor fixes & more unit tests:
- Fix bug: if one linter returns errors and another returns errors:[], the
no-errors linter is shown in the panel as an empty heading. (Bug doesn't
happen if it returned null instead; but both are valid ways of indicating
zero errors).
- Improve docs on register() - more concise, more detail on how to indicate
zero errors
- Add unit tests for the bug fixed above plus several more async linting
cases that were fixed late in PR #6530
- Fix mislabeled existing unit test for reject()ing async linters
- Fix stray whitespace that snuck into merge c3411bb7
Highlight Selection Matches
Make getModeForRange() behave like getModeForSelection() when mode is not mixed
Merge pull request #7775 from adobe/nj/issue-7764

Make getModeForRange() behave like getModeForSelection() when mode is not mixed
Use new underline style
sprint 40
Merge pull request #7778 from adobe/set-sprint-40

sprint 40
Spanish Translations for Sprint 39
Merge pull request #7780 from adobe/tom/spanish-39

Spanish Translations for Sprint 39
Merge pull request #7748 from adobe/tom/highlight-matches

Highlight Selection Matches
Give a more specific error message in cases where Brackets refuses to open
a file that is not UTF-8 (message is also shown when trying to open binary
files).

The right error code is already returned from the native shell -- we just
need to plumb it down to FileSystem and add a case-specific string for it.
Merge pull request #7787 from adobe/pflynn/encoding-error-string

More specific error message when non-UTF-8 files opened
Merge pull request #7793 from adobe/release

Merge release back into master to trigger ALF localization update
Merge pull request #7650 from adobe/pflynn/lint-tests-fixes

Code Inspection: minor fixes & more unit tests