Event keyword is not highlighted when assigned to a lambda expression

[DustinCampbell]

From @zEh- on May 16, 2018 20:5

Issue Type: Bug

public event OnOpen onClose = () => { };

Syntax: "event" is not highlighted as a keyword is white instead of blue

Extension version: 1.15.2
VS Code version: Code 1.23.1 (d0182c3417d225529c6d5ad24b7572815d0de9ac, 2018-05-10T17:11:17.614Z)
OS version: Windows_NT x64 10.0.17134

System Info

Item	Value
CPUs	AMD Ryzen 7 1700X Eight-Core Processor (16 x 3400)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: disabled_software video_decode: enabled video_encode: enabled vpx_decode: enabled webgl: enabled webgl2: enabled
Memory (System)	15.95GB (8.09GB free)
Process Argv	C:\Program Files\Microsoft VS Code\Code.exe
Screen Reader	no
VM	0%

Copied from original issue: dotnet/vscode-csharp#2315