need type open and close php tags for code fragment

[Eskander88]

Description

Why need typing open and close tag for php code, when that doesn't do for: html, javascript, etc..

Steps to Reproduce

1. Type text with php-code, as screen
   

2. Run Markdown Preview: Toggle

3. See the result Markdown Preview: Toggle

Expected behavior: Need both variants highlighting

Actual behavior: A first variant show without highlight syntax. Second part with open and close php-tag is higlighted.

Reproduces how often: 100%

Version

Atom    : 1.27.0-beta1
Electron: 1.7.11
Chrome  : 58.0.3029.110
Node    : 7.9.0

OS: Windows 10 x64