Adds failing spec

[davidwessman]

It took a while for me to find the correct error case, but this key is invalid when parsed by the PatternWithScopeScanner causing the errors in #520

@glebm any suggestion for regex to fix this?

Failure/Error: expect(scanner.keys.map(&:key)).to eq(['test.N#{n["key"]}'])
     
       expected: ["test.N\#{n[\"key\"]}"]
            got: ["test.N\#{n["]
     
       (compared using ==)
     # ./spec/pattern_with_scope_scanner_spec.rb:91:in `block (3 levels) in <top (required)>'

[glebm]

This may be tricky to fix with a regex.

Currently it is defined here:

i18n-tasks/lib/i18n/tasks/scanners/ruby_key_literals.rb

Line 5 in d045392

LITERAL_RE = /:?".+?"|:?'.+?'|:\w+/.freeze

A possible workaround is to dissallow letters and ] immediately after the ".
This can be done using a negative lookahead, e.g.:

LITERAL_RE = /^:?(["']).+?\1(?![\p{L}\]])|:\w+/.freeze

https://rubular.com/r/g77VbORrgrqZdx

Disallowing ] would mean the following contrived example would fail though:

[t 'a.b.c']