Improve generateEditorConfig example in docs

[BD103]

Description

I deleted a duplicate command in the documentation. (ktlint generateEditorConfig) I don't believe it was intentional.

I figured the fix was simple enough that adding an extended description to the commit message is not necessary. I can change this, though.

I added the fix to both the snapshot and release documentations. It's not necessarily pressing enough to need being updated in the release version, but I figured it couldn't do too much harm.

Checklist

Before submitting the PR, please check following (checks which are not relevant may be ignored):

• Commit message are well written. In addition to a short title, the commit message also explain why a change is made.
• At least one commit message contains a reference Closes #<xxx> or Fixes #<xxx> (replace<xxx> with issue number)
• Tests are added
• KtLint format has been applied on source code itself and violations are fixed
• PR title is short and clear (it is used as description in the release changelog)
• PR description added (background information)

Documentation is updated. See difference between snapshot and release documentation

• Snapshot documentation in case documentation is to be released together with a code change
• Release documentation in case documentation is related to a released version of ktlint and has to be published as soon as the change is merged to master

[paul-dingemans]

The documentation is indeed not correct. It would be better to change it something like below:

ktlint generateEditorConfig
# or
ktlint generateEditorConfig intellij_idea
# or
ktlint --ruleset=/path/to/custom-ruleset.jar generateEditorConfig  android_studio```

The idea was that to demonstrate that if no code style is provided that `ktlint_official` is used as default. If you want another code style then you need to provide the id of that code style.

[BD103]

Ok, I've updated the example. :)