"This variable must either have a type annotation or be initialized" when first calling constructor and then prepending the variable initialization

Reproduce:
1. First call the constructor eg:
```kotlin
BufferedReader(reader)
```
2. Prepend that line with the variable declaration/initialization
```kotlin
val buf = BufferedReader(reader)
```
3. Errors with above message

Reproduce the two-step Kotlin example in the language server and capture the diagnostic after prepending the declaration. Trace the handling of constructor calls and variable declarations to identify where the erroneous type-annotation message is produced, then add a regression test showing that the initialized declaration is accepted.

Written by the indexing model from the issue text.