Razor implicit/explicit expressions in HTML attributes are not colored properly

[NTaylorMullen]

Our TextMate grammar doesn't look like it properly supports Razor expressions in HTML attributes.

Easiest way to repro is to create a new Blazor project and then open NavMenu.razor. There's this line that doesn't colorize correctly:

<div class="@NavMenuCssClass" @onclick="ToggleNavMenu">

[NTaylorMullen]

This impacts the immediate colorization experience of the Razor editor in default templates. Pulling into our alpha release.

[TanayParikh]

FYI: @ryanbrandenburg @noahbkim

Sample Text to try this out during validations (screenshots of before / after are in the PR).

Explicit

<div class="@(NavMenuCssClass)"></div>
<button @onclick="@(ToggleNavMenu())"></button>
<button @onclick="@()"></button>
<button @onclick="@(DateTime.Now)"></button>
<button @onclick="@(456 + new Array<int>(){1,2,3}[0] + await GetValueAsync<string>() ?? someArray[await DoMoreAsync(() => {})])"></button>

<button @onclick="@(
    Html.BeginForm(
        "Login",
        "Home",
        new
        {
            @class = "someClass",
            notValid = Html.DisplayFor<object>(
                (_) => Model,
                "name",
                "someName",
                new { })
        })
)"></button>

Implicit

<div class="@NavMenuCssClass"></div>
<button @onclick="@ToggleNavMenu()"></button>
<button @onclick="ToggleNavMenu"></button>
<button @onclick="abc@DateTime.Now"></button>
<button @onclick=")@DateTime.Now"></button>
<button @onclick=".@DateTime.Now"></button>
<button @onclick="}@DateTime.Now"></button>
<button @onclick="@"></button>
<button @onclick="@DateTime.Now{"></button>
<button @onclick="@DateTime.Now}"></button>
<button @onclick="@DateTime.Now)"></button>
<button @onclick="@DateTime.Now]"></button>
<button @onclick="@DateTime.Now"></button>
<button @onclick="@await AsyncProperty"></button>
<button @onclick="@await AsyncMethod()"></button>
<button @onclick="@DateTime!.Now()[1234 + 5678](abc()!.Current, 1 + 2 + getValue())?.ToString[123](() => 456)"></button>
<button @onclick="<p>@DateTime.Now</p>"></button>

<button @onclick="@DateTime!.Now()[1234 +
        5678](
        abc()!.Current,
        1 + 2 + getValue())?.ToString[123](
        ()=>
    {
    var x = 123;
    var y = true;

    return y ? x : 457;
    })">
</button>