`If` block with whitespace control is mutated during transform

[tylerturdenpants]

Given:

{{#if foo~}}
  {{foo}}
{{/if}}

Expected:

{{#if foo~}}
  {{foo}}
{{/if}}

Actual:

{{#if foo~}}{{foo}}
{{/if}}

[rwjblue]

Can you submit a failing test case?

Sorry, I didn't notice that #156 is that failing test case...

[rwjblue]

I created handlebars-lang/handlebars.js#1584 to make this much nicer. At the moment the text nodes after the whitespace are completely removed from the AST, so we can't easily "fix" the reported problem.

Once that PR lands (and is released) we can:

1. update handlebars version in @glimmer/syntax
2. tweak the codemod option details to use disableWhitespaceControl (instead of ignoreStandalone)
3. release @glimmer/syntax
4. update @glimmer/syntax here
5. release an update