Handlebars syntax highlighter does not recognize end of comment when using whitespace control (~) before closing braces

[alexr00]

Bug Description

In Handlebars templates, VSCode's syntax highlighting fails to properly recognize the end of a comment block when a whitespace control character (~) is used just before the closing delimiter. As a result, the line following the comment is incorrectly highlighted as if it were still part of the comment.

The following snippet demonstrates the bug:

    {{!-- This is a comment --~}}
    But this is not

The second line, But this is not, is rendered as a comment, but it should not be.

Steps to Reproduce:

1. Paste the following Handlebars code into a .hbs file in VSCode:

   {{!-- This is a comment --~}}
   But this is not

2. Observe the syntax highlighting of the second line.

Expected:

• Only the first line should be highlighted as a comment.
• The second line should be highlighted as normal Handlebars content.

Actual:

• The second line is improperly highlighted as a comment.

Notes:

• This issue occurs with the built-in Handlebars syntax highlighting in the latest VSCode version.
• The bug seems to be specific to comments that use the Handlebars whitespace control character (~) before the closing braces.
• Extensions disabled: Yes (still reproduces)
• VS Code Version: 1.123.0
• OS Version: MacOS 26.5

Originally from @jmpri3 in microsoft/vscode#320133