[html] bracket matching in strings

Issue Type: <b>Bug</b> In HTML the minor sign inside of tags is sometimes recognised as opening a new tag. For Example: `<div data-ng-if="(something <= 0)" class="alert alert-warning">`  VS Code version: Code 1.32.3 (a3db5be9b5c6ba46bb7555ec5d60178ecc2eaae4, 2019-03-14T23:43:35.476Z) OS version: Windows_NT x64 10.0.16299 <details> <summary>System Info</summary> |Item|Value| |---|---| |CPUs|Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz (4 x 2494)| |GPU Status|2d_canvas: enabled<br>checker_imaging: disabled_off<br>flash_3d: enabled<br>flash_stage3d: enabled<br>flash_stage3d_baseline: enabled<br>gpu_compositing: enabled<br>multiple_raster_threads: enabled_on<br>native_gpu_memory_buffers: disabled_software<br>rasterization: unavailable_off<br>surface_synchronization: enabled_on<br>video_decode: enabled<br>webgl: enabled<br>webgl2: enabled| |Memory (System)|7.94GB (3.81GB free)| |Process Argv|| |Screen Reader|no| |VM|0%| </details><details><summary>Extensions (3)</summary> Extension|Author (truncated)|Version ---|---|--- python|ms-|2019.2.5558 cpptools|ms-|0.22.1 vscode-spotify|shy|3.1.0 (2 theme extensions excluded) </details> <!-- generated by issue reporter -->