pager: translate additional strings
translations: Add portuguese translation
Suppress PATH errors in sudo tab-completion

Setting a non-existant path component to PATH logs an error to stderr.
This is not appropriate for non-interactive temporary modifications,
like the one done by the `sudo` completion helper function.
make_tarball: build from the current checkout, ignore Travis
Clean up typos and style in design doc

This includes:

- Fixing some typos and misspellings
- Being consistent with pronouns (she/he)
- Hyphenating "built-in" and "command-line" where appropriate
Merge remote-tracking branch 'upstream/master' into documentation-update

Conflicts (resolved):
	doc_src/design.hdr - \c changed to backticks