[BUG] Update grammar.ebnf #608

[Ph0enixKM]

This file exists so that external developers can easily create plugins interpreting Amber's syntax (syntax highlighting etc.). This file provides necessary information of how the syntax is being parsed from the more abstract (high level) point of view.

[hdwalters]

Also consider either (i) adding these keywords already supported in the Vim plugin, (ii) advising me which ones to remove from the Vim plugin, or (iii) marking them as from older versions of Amber, and hard-coding (e.g. unsafe) in the Amber script you proposed:

break
continue
fail
is
ref
return
status
unsafe

[Ph0enixKM]

@hdwalters updated

[hdwalters]

It might also be helpful to (i) make the script executable, and (ii) echo the sorted keywords on separate lines:

$ amber keywords.ab 
and
as
break
cd
const
...

[Ph0enixKM]

Concerns addressed

[Ph0enixKM]

Done