aspnetcore: Razor compiler produces incorrect markup content for single-quoted attributes

Repro: Create a .razor file containing:

<button onclick='alert("hello")'>Click me</button>

Compiled result:

__builder.AddMarkupContent(0, "<button onclick=\"alert(\"hello\")\">Click me</button>");

This is incorrect because the double-quotes inside the attribute haven’t been encoded in any way. At runtime, clicking on the button will produce an error (SyntaxError: Unexpected end of input).

Expected result: Something like

__builder.AddMarkupContent(0, "<button onclick=\"alert(&quot;hello&quot;)\">Click me</button>");

Or even:

__builder.AddMarkupContent(0, "<button onclick='alert(\"hello\")'>Click me</button>");

Do we claim to support single-quoted attributes fully in Razor?

cc @ajaybhargavb @NTaylorMullen