[C/C++] Line continuation in some expressions inside macros not highlighted

[deathaxe]

All expressions which push a context to stack cause the macro line continuation not to be highlighted which may cause the syntax of the expression to break due to the unexpected \ token.

Example:

# define CASE_4 case \
    4:

Related with #1333

[rwols]

Also related: https://github.com/sublimehq/Packages/issues/1107