feat(core): add sentence-case to ensure-case

[Rugal]

1. Add standard-case rule
2. Add test cases

[marionebl]

Thanks for the contribution!

If I understand this correctly you want to enable the use case raised as being unsupported in #114, where one wants to check if the first letter of the subject is capitalized or not, e.g.

# config: [2, 'never']
# subject-case: [0]
echo "type: Foo Bar" | commitlint # throws for new rule
echo "type: foo Bar" | commitlint # passes 
echo "type: foo bar" | commitlint # passes

# config: ['2', 'never']
# subject-case: [2, 'always', 'lowercase']
echo "type: Foo Bar" | commitlint # throws for new rule, subject-case
echo "type: foo Bar" | commitlint # throws
echo "type: foo bar" | commitlint # passes

# config: ['2', 'always']
# subject-case: [2, 'always', 'lowercase']
echo "type: Foo Bar" | commitlint # throws for subject-case
echo "type: foo Bar" | commitlint # throws for subject-case
echo "type: foo bar" | commitlint # passes

I'd prefer to put this into a distinct rule named subject-leading-case, what do you think?

[Rugal]

Hi @marionebl,

Thanks for the reply.

Actually I have this requirement from myself, where I want to have the first letter of a capture group to be uppercase. This not only applies for subject, but also for the others, like type, scope etc.

With that said, making it a rule that different from the xxx-case rule might cause collision.
For instance, I specify subject-case = lowercase and subject-leading-case = uppercase, which would be problematic, hence, I think it is better to create a case rather than a separate rule.

What's your opinion?

[marionebl]

Ok, I can follow your reasoning here - avoiding the complexity of handling the collision of *-case vs. *-leading-case is a good thing.

Do you have a reference for calling this standard-case?

I'd lean towards renaming this to sentence-case:
https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage

Also, it would be awesome if you could extend the rule docs accordingly to your changes.

[Rugal]

Awesome, I am good with the renaming.
I will rename it to sentence-case and add some docs.

[Rugal]

@marionebl Please rerun appveyor CI.

[Rugal]

@marionebl This duplicates the docs I added, please see 3 lines below.

[marionebl]

Thanks, deduped it