Shell command in back quotes with <<

[psycho-coder]

Issue Type: Bug

Highlight be broken if script has back quotes with <<.
Example:

1. Create file test.sh
2. Open test.sh and paste example below

CHANGELOG=`cat << EOF
nginx ($VER-2~$REL) $REL; urgency=low

• $VER

-- $CONTRIB_NAME <$CONTRIB_EMAIL> $DATE
EOF`

3. Write code below CHANGELOG.

Gist with example
All code below back quotes will be highlighted as 'shell code'.

VS Code version: Code 1.44.2 (ff91584, 2020-04-16T17:07:18.473Z)
OS version: Darwin x64 17.7.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz (4 x 2500)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: unavailable_off rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off_ok webgl: enabled webgl2: enabled
Load (avg)	3, 3, 3
Memory (System)	8.00GB (0.02GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions: none

[alexr00]

Moved to owning repo: atom/language-shellscript#158

[alexr00]

Closing in favor up the upstream issue.