Visual studio code 1.14 is out. One new feature is auto-indent, however to support this the language-configuration.json needs regex patterns to recognize when to indent and when to unindent, namely decreaseIndentPattern, increaseIndentPattern and indentNextLinePattern which is not mentioned in the first link. The language-configuration.json lies directly in the visual studio code reposority.
The most common case of indentation and unindentation is with { and }, however there are also some more complex cases like multi-line #![]-statements, function definition parameters, function call parameters, etc.
It would be nice to have regexes that support all those cases.