Shellcheck scripts

[0x647262]

Reasoning:

I opened this issue for 3 reasons:

1. I read through this repository's shell scripts and noticed a handful of parts which could use refactoring.
2. Implementing some of shellcheck's suggested fixes can prevent potential edge-case problems from manifesting themselves.
3. The main reason: I want to become more comfortable with bot-ci's codebase.

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Plan:

• Individual PRs for each script to make each set of changes much easier to review.

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Scope:

• [ ] ssh/ssh_wrapper.sh - Could be skipped
• [ ] ci/sync-mirrors.sh - Could be skipped
• [x] ci/doc-index.sh
• [x] ci/pvs-report.sh
• [ ] ci/translation-report.sh
• [ ] ci/assign-labels.sh
• [ ] ci/clint-errors.sh
• [ ] ci/deps-src.sh
• [ ] ci/common/neovim.sh
• [ ] ci/common/github-api.sh
• [ ] ci/common/dependencies.sh
• [ ] ci/common/deps-repo.sh
• [ ] ci/common/html.sh
• [ ] ci/common/common.sh
• [ ] ci/common/doc.sh
• [ ] ci/common/badge.sh
• [ ] ci/package-macos.sh
• [ ] ci/sync-lp-mirrors.sh
• [ ] ci/nightly.sh
• [ ] ci/vimpatch-report.sh
• [ ] ci/clang-report.sh
• [ ] ci/doxygen.sh
• [ ] ci/user-docu.sh
• [ ] scripts/travis-setup.sh

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Thoughts?

[justinmk]

Sounds good, start with 1 script and we can set expectations from that.

[justinmk]

this issue is very outdated (scripts changed)