Update code_examples.nl

Changed assigment from '=' to ':='
Removed 'asString' calls
Changed 'Block a = [].' to '[] a.'
Changed '[ (ReturnType) ... ].' to '[ ReturnType ...].'
Changed '[] = primitive.' to 'primitive [].'
Removed 'type Type = abstract'
Changed '[] = abstract.' to 'abstract [].'
Changed '[ aBlockName ]' to '[] aBlockName'.
Changed '[ Boolean or: [ Boolean ] ]' to '[ Boolean or [ Boolean ] ]'
Changed '[ Boolean and: [ Boolean ] ]' to '[ Boolean and [ Boolean ] ]'
Changed emtpy block definition '[ ... | ]' to '[ ... ]'

Update vim/syntax/nl.vim

Removed 'using' and 'as' keywords
Changed some highlight groups like 'type' and 'static'