Incorrect syntax highlighting with YAML plain flow scalar multiline strings

[izhess]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.60.2
• OS Version: macOS Big Sur, Version 11.6

Steps to Reproduce:

1. Write YAML with multiline string, like this:

bar: Multiline start
  | newline pipe character is valid in Plain Flow Scalar, but is highlighted as error
baz: quux

2. Save the YAML-file and notice the syntax highlight is incorrect:

[mkjor]

I found a similar issue with the handling of multiline text. If the 2nd and following lines are beginning with a -, the syntax highlighting formats the - as an array element.

For example:

array:
  - entry 1
  - entry 2
string: Line 1
  - line 2
  - line 3

is rendered as

There is no visible difference of the array and string.

Hint: The GitHub highlighting has the same problem 😄

[alexr00]

Upstream issue: textmate/yaml.tmbundle#28