Some expression parts not highlighted in GString expressions

[eric-milles]

Non-specific expression parts within GString expressions are colored as strings.

"Blah blah ${Arrays.asList('one', 'two')}" // 'Arrays.', '(' and ',' are colored as strings
"Blah blah ${ -> ... }" // '->' is colored as string"

$, ${ and } are also colored as strings and may be highlighted otherwise to indicate their special nature.

[eric-milles]