grammar.adoc is missing grammar for initializer and initializer_list rules

[TobyCharlton]

grammar.adoc is missing grammar for initializer and initializer_list rules
initializer : is empty
initializer_list : does not exist

[rlocatti-nv]

Hello. The definitions are there, but they are not being rendered by the GitHub preview. They are wrapped around ifdefs like this:

_initializer_ : ::
ifdef::GLSL[]
    _assignment_expression_ +
    _LEFT_BRACE_ _initializer_list_ _RIGHT_BRACE_ +
    _LEFT_BRACE_ _initializer_list_ _COMMA_ _RIGHT_BRACE_

_initializer_list_ : ::
    _initializer_ +
    _initializer_list_ _COMMA_ _initializer_
endif::GLSL[]
ifdef::ESSL[]
    _assignment_expression_
endif::ESSL[]

There are other instances, the raw file can be found here.