[yaml] highlighting issue with backslash

[oneslash]

Issue Type: Bug

YAML: Highlighting has a problem, refer to the screenshot.

text

    - name: Backup staging db
      shell: |
        mysqldump \
          -h {{ lts_mysql_host }} \
          -u {{ lts_mysql_user }} \
          -p {{ lts_mysql_password }}  \
          --max_allowed_packet=512M \
          {{ lts_mysql_database }} \
      tags:
        - lts-staging

VS Code version: Code 1.23.1 (d0182c3, 2018-05-10T16:03:31.083Z)
OS version: Darwin x64 17.5.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-7267U CPU @ 3.10GHz (4 x 3100)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled video_decode: enabled video_encode: enabled vpx_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	16.00GB (0.45GB free)
Process Argv	/Applications/Visual Studio Code.app/Contents/MacOS/Electron
Screen Reader	no
VM	0%

Extensions (19)

Extension	Author (truncated)	Version
vscode-docker	Pet	0.0.27
gitignore	cod	0.5.0
systemd-unit-file	coo	1.0.0
vscode-eslint	dba	1.4.10
ansible-vault	dho	0.1.3
tslint	eg2	1.0.30
vscode-npm-script	eg2	0.3.4
terraform-autocomplete	erd	0.0.8
flow-for-vscode	flo	0.8.1
terraform	mau	1.1.2
dotenv	mik	1.0.1
python	ms-	2018.4.0
cpptools	ms-	0.17.3
Go	ms-	0.6.80
jenkinsfile-support	sec	0.1.0
vscode-nginx	sha	0.5.0
cmake	twx	0.0.17
vscode-react-native	vsm	0.6.10
jinja	who	0.0.8

(1 theme extensions excluded)

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Setting language specific tab size gets reset (#46394)
• Support JSON Schema for YAML files (#1176)
• VSCode Version 1.23.1 reintroduces yaml formatting bug (#49770)

[oneslash]

Unlike in #49770 restart didn't help

[aeschli]

This issue was moved to textmate/yaml.tmbundle#25