fix: errors quote

[zce]

- "error: missing required argument `%s'"
+ "error: missing required argument '%s'"

[kira1928]

@zce
Your pr broke the lint test.
https://travis-ci.org/tj/commander.js/jobs/493226140#L464-L478
I think those single quotes were inserted to cheat eslint, which is a bad practice :(
Could you change the https://github.com/tj/commander.js/blob/master/.eslintrc.json file to allow only double quotes or change all those strings to be wrapped by single quotes?
(BTW, I personally prefer double quotes :p)

[shadowspawn]

I have some comments too @zce. Sorry, you probably through it was an easy pull request!

1. What problem are you fixing? Personally I do not like how the left/right quotes look and it is unusual, is that what you are fixing? e.g. currently

error: missing required argument `text'

2. what cli commands have you looked at? The examples I found all used straight single quotes:

$ git silly 
git: 'silly' is not a git command. See 'git --help'.
$ hg silly
hg: unknown command 'silly'
$ cc silly
clang: error: no such file or directory: 'silly'

3. An observation for how much this affects people (i.e. semver). The change does not affect functionality, but some people will have designed their own error commands to match this style and will care if we change the style.

[zce]

error: missing required argument `text'

`text' starts with right quotes, but ends with straight single quotes

[shadowspawn]

I found an OLD reference to this very issue: https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html

I would prefer

'unexpected'

rather than

`unexpected`

(although I have to admit I am now recognise the left quote from markdown, but keep it simple!)

[shadowspawn]

Although this does not change the functionality, some people will have written their own error messages to match commander style (so I suggest at least semver:minor), and some smaller number may be parsing error messages to do custom handling (so we could be paranoid and include in a semver:major).

Consider whether you think semver patch or minor or major when you review @abetomo or @vanesyan, and comments welcome from any readers.

[abetomo]

Thank you!
I think 'unexpected' is good.

[shadowspawn]

Oops, I forgot to formally review this myself! Thanks @abetomo

Thanks for earlier changes @zce. Looks good to me.

[shadowspawn]

Merging into release/3.0.0 branch.

[shadowspawn]

Already had two approvals. Merged into v3 and will be included in that release. Closing to make it clear that should not be merged into master.

Thank you for your contributions.

[shadowspawn]

Available now as a prerelease. See #1001

[shadowspawn]

Shipped in v3: https://github.com/tj/commander.js/releases/tag/v3.0.0