Wrong raw string literal highlighting

[gaudat]

Environment data

• VS Code version: 1.26.1
• Extension version (available under the Extensions sidebar): 2018.7.1
• OS and version: Windows 10 64-bit, build 17134
• Python version (& distribution if applicable, e.g. Anaconda): Python 3.6.3, Anaconda 4.2.0
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): N/A
• Relevant/affected Python packages and their versions: N/A

Actual behavior

Backslashes are highlighted as escape characters when a raw string wrapped with lower case r"" but not upper case R"".

Expected behavior

Backslashes should not be highlighted as escape characters.

Steps to reproduce:

1. Type

big_r = R"C:\Users\me\"
small_r = r"C:\Users\me\"

on a new file with Python code highlighting.

Logs

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

(Nothing)

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help)

 INFO standard startup Object
console.ts:136 [Extension Host] activating extension
console.ts:136 [Extension Host] Starting express server on port: 1136
console.ts:136 [Extension Host] using C:/Users/anon/.vscode/extensions/vsciot-vscode.vscode-arduino-0.2.20/vendor/node-usb-native/lib/native/usb-native_win32_2.0.2_x64.node
console.ts:136 [Extension Host] Python Extension: Failed to get conda environment list from conda Error: spawn conda ENOENT
	at _errnoException (util.js:1024:11)
	at Process.ChildProcess._handle.onexit (internal/child_process.js:190:19)
	at onErrorNT (internal/child_process.js:372:16)
	at _combinedTickCallback (internal/process/next_tick.js:138:11)
	at process._tickCallback (internal/process/next_tick.js:180:9)

[brettcannon]

We actually don't provide the syntax highlighting, VS Code does. And they get their highlighting from https://github.com/MagicStack/MagicPython, so it would be best to report it to them.