Grammar Injection doesn't not work on multi-line content

[r-laf]

I tried to inject TOML grammar into markdown, however the TOML colorizer only works on the first line (i.e. a = "b" in the image), it doesn't work on the following line (i.e. d = "c" in the image)

My tmLanguage.json for the injection is like:

{
	"fileTypes": [],
	"injectionSelector": "text.html.markdown",
	"name": "tomlfrontmatter",
	"patterns": [
		{
			"begin": "\\Abegin\\s*",
			"end": "(^|\\G)end\\s*$",
				
				"patterns": [
					{
						"include": "source.toml"
					}
				]
		}
	],
	"scopeName": "toml.frontmatter.markdown"
}

The complete source code is at: https:/zh4ui/vscode-markdowntoml.git

• VSCode Version: Version 1.17.2 (1.17.2)
• OS Version: macOS 10.13 (17A405)

Steps to Reproduce:

1. install the Better TOML for TOML colorizer
2. git clone https:/zh4ui/vscode-markdowntoml.git
3. cd vscode-markdowntoml && code .
4. F5 to debug the code
5. Create a markdown file in the [Extension Development Host]
6. type in the content

begin a = "b"
c = "d"
end

Reproduces without extensions: No

[mjbvz]

This issue was moved to microsoft/vscode-textmate#57