Miscellaneous style and docs improvements

[mhauru]

Small typo fixes and a couple of docstring improvements. These are things I picked up as I was reading the code to understand it.

[coveralls]

Pull Request Test Coverage Report for Build 9563441562

Details

• 5 of 10 (50.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.7%) to 79.623%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/context_implementations.jl	0	5	0.0%

Totals
Change from base Build 9495604846:	-0.7%
Covered Lines:	2743
Relevant Lines:	3445

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9563441562

Details

• 5 of 10 (50.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.03%) to 80.326%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/context_implementations.jl	0	5	0.0%

Totals
Change from base Build 9495604846:	-0.03%
Covered Lines:	2756
Relevant Lines:	3431

---

💛 - Coveralls

[torfjelde]

Note that there's quite a rework on the transformation side in the works: #575 . I started working on this again today. After that, vectorize will be replaced + not used as extensively. You can see a description in the doc-preview: https://turinglang.org/DynamicPPL.jl/previews/PR575/internals/transformations/

[mhauru]

I rebase this on master and left only the relevant changes. Ready for review now.

[coveralls]

Pull Request Test Coverage Report for Build 10669973054

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 19 unchanged lines in 2 files lost coverage.
• Overall coverage remained the same at 77.508%

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Files with Coverage Reduction	New Missed Lines	%
src/model.jl	1	88.46%
src/threadsafe.jl	18	49.57%

Totals
Change from base Build 10652412131:	0.0%
Covered Lines:	2712
Relevant Lines:	3499

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💛 - Coveralls