nvda

133a812e - Add some missing translator comments and check for missing translator comments in future.

Add some missing translator comments and check for missing translator comments in future. 1. Translators reported that some new translatable strings introduced in PR #7258 were missing translator comments. Add translator comments for these. 2. Add some code (`checkPot`) to check for missing translator comments in the translation template (pot). For now, we have a set of expected failures, since fixing all existing 87 messages that don't have translator comments is going to take some work. However, we want to fail for any new messages that get introduced without comments. 3. Run `checkPot` as part of `scons tests`. This means tests (and thus builds) will fail so we learn about these problems early. 4. `checkPot` can also be run alone with `scons checkPot`. 5. Now that `scons tests` runs `checkPot` (which depends on `pot`), don't explicitly run `scons pot` on AppVeyor.