sidekick: fix xref link to escaped methods

When the method is escaped we get warnings like this:

```
warning: '`get`(request:options:)' doesn't exist at '/GoogleCloudComputeV1/ImagesClient'
--> ../images+Requests.swift:135:61-135:84
133 | }
134 |
135 + /// Synthetic request message for the [get()][google.cloud.compute.v1.images.get] method.
| ├─suggestion: Replace '`get`(request:options:)' with 'get(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'getIamPolicy(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'getFromFamily(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'delete(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'insert(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'list(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'deprecate(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'setLabels(request:options:)'
| ├─suggestion: Replace '`get`(request:options:)' with 'patch(request:options:)'
| ╰─suggestion: Replace '`get`(request:options:)' with 'setIamPolicy(request:options:)'
136 | ///
137 | /// [google.cloud.compute.v1.images.get]:
```

Changing xref link to this fixes the warning:

```
137 | /// [google.cloud.compute.v1.images.get]:
```

Start with the generated images+Requests.swift file around lines 135-137 and inspect the xref for ImagesClient/get(request:options:). Compare the escaped and unescaped method links, then run the relevant documentation or generation check to confirm the warning is gone and the cross-reference resolves correctly.

Written by the indexing model from the issue text.