Including a comment in a `@template/value` causes an unexpected template error

**What steps did you take:**

Adding a comment after setting a value for a node...

```yaml
list_with_a_map: #@ some_list #! including this comment fails
```

**What happened:**
Results in an error:

```
- got identifier, want ')'
yaml.yml:1 | list_with_a_map: #@ some_list #! including this comment fails
yaml.yml:? | __ytt_tpl2_end_ctx(None) (generated)
```

**What did you expect:**

For the comment to simply be ignored.

**Anything else you would like to add:**

- reported [#carvel ~ 2021-07-16](https://kubernetes.slack.com/archives/CH8KCCKA5/p1626440295463700) by @larssb
- reported [#carvel ~ 2022-05-31](https://kubernetes.slack.com/archives/CH8KCCKA5/p1652477858157579) by @voor

**Environment:**

- ytt version (use `ytt --version`): v0.40.1
- OS (e.g. from `/etc/os-release`): *

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