Fix false negatives for SVG keywords and add option: ["camelCaseSvgKeywords"] to value-keyword-case

[kawaguchi1102]

Which issue, if any, is this issue related to?

Closes #4884

Is there anything in the PR that needs further explanation?

Following the discussion in the issue thread, I have added a rule option.
I hope this will satisfy your request.

[ybiquitous]

@kawaguchi1102 Thanks for creating the pull request!

[ask] @jeddy3 said on #4884 (comment):

We change the default behaviour so that the primary option (lower or upper) is used for every keyword, and add a camelCaseSvgKeywords: true option for users who want the existing behaviour.

so, when camelCaseSvgKeywords: false (this is the changed default behavior?), should currentcolor be always correct, not currentColor?

[jeddy3]

so, when camelCaseSvgKeywords: false (this is the changed default behavior?), should currentcolor be always correct, not currentColor?

That's correct. This pull request should also fix the false negatives, i.e. currentColor, optimizeLegibility etc should be lowercase if "lower" is the primary option and if camelCaseSvgKeywords is set to false or not set at all.

[jeddy3]

@kawaguchi1102 Thanks for the pull request.

As @ybiquitous implied, the logic needs inverting i.e. when the camelCaseSvgKeywords option is set to true the SVG keywords should be camel case regardless of the primary option. When the it is set to false or not set, then the primary option, e.g. lower or upper, should be respected.

[kawaguchi1102]

Thank you for pointing out the mistake.
I was mistaken in my assumption.

I will fix this issue.

[jeddy3]

Turns out the SVG keywords were only camelCase for the "lower" primary. I've aligned this new option with that, as well as patching up the logic and tests.

If true, this rule expects SVG keywords to be camel case when the primary option is "lower".

LGTM.

[ybiquitous]

LGTM👍

[jeddy3]

• Added: camelCaseSvgKeywords to value-keyword-case - use this option if you want legacy camel case SVG keywords like currentColor (#5849).

• Fixed: value-keyword-case false negatives for SVG keywords like currentcolor (#5849).