C# Syntax Highlighting Bug for Tuples & Multilined Variables

Originally from @AharonSambol in https://github.com/microsoft/vscode/issues/135031

## Details

What editor are you seeing the problem in? (e.g. Atom, Visual Studio Code, etc.)
VS Code

What version of the editor are you using?
1.61

What color theme are you using?
N/A as the issue is with the scopes that the tokens are getting.

## Repro


Steps to reproduce:
Open a blank C# project and paste the following code:

public class ExClass {

public static int correctColor; // example for correct color
public static int
value1, value2; // example for incorrect color (should be light blue not white)
}
public class Program {
void Func(){
ExClass.value1 = 1; // example for correct color
(ExClass.value1, ExClass.value2) = (1,2); // example for incorrect color (ExClass should be light blue not white)
}
}

The type of the variables doesn't matter.

VS Code version: Code 1.61.0 (ee8c7def80afc00dd6e593ef12f37756d8f504ea, 2021-10-07T18:13:09.652Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No

System Info

|Item|Value|
|---|---|
|CPUs|Intel(R) Core(TM) i7-9700KF CPU @ 3.60GHz (8 x 3600)|
|GPU Status|2d_canvas: enabled
gpu_compositing: enabled
multiple_raster_threads: enabled_on
oop_rasterization: enabled
opengl: enabled_on
rasterization: enabled
skia_renderer: enabled_on
video_decode: enabled
vulkan: disabled_off
webgl: enabled
webgl2: enabled|
|Load (avg)|undefined|
|Memory (System)|15.92GB (9.33GB free)|
|Process Argv|--crash-reporter-id b5a2ba25-e8a3-43d1-af6e-d42f94d5c410|
|Screen Reader|no|
|VM|0%|
Extensions (1)

Extension|Author (truncated)|Version
---|---|---
csharp|ms-|1.23.16

A/B Experiments

```
vsliv368:30146709
vsreu685:30147344
python383cf:30185419
pythonvspyt602:30300191
vspor879:30202332
vspor708:30202333
vspor363:30204092
vswsl492:30256859
pythonvspyt639:30300192
pythontb:30283811
pythonvspyt551:30345470
pythonptprofiler:30281270
vshan820:30294714
vstes263cf:30335440
vscorecescf:30358481
pythondataviewer:30285071
pythonvsuse255:30340121
vscod805cf:30301675
pythonvspyt200:30340761
binariesv615:30325510
vsccppwtct:30378365
pythonvssor306:30344512
bridge0708:30335490
pygetstartedt2:30371810
dockerwalkthru:30377721
bridge0723:30353136
pythonrunftest32:30373476
pythonf5test824:30373475
javagetstartedc:30364665
pythonvspyt187:30373474
vsqsis400:30381677
vsaa593cf:30376535
vssld246:30379911

```

Inizia con la grammatica di evidenziazione della sintassi C# utilizzata dal progetto dotnet/csharp-tmLanguage e riproduci gli esempi in VS Code 1.61. Confronta i token scopes per le dichiarazioni di variabili su più righe e le assegnazioni di tuple; il lavoro è completato quando gli identificatori interessati ricevono gli scopes previsti in entrambi gli esempi.

Scritto dal modello di indicizzazione a partire dal testo della issue.