Symbol rename doesn't rename all occurences

### Describe the Bug

In VSCode and neovim, when renaming symbol, if variable is reassigned (or was assigned before), it will be treated as a different symbol

Example:

```python
val = 1
val = val + 1
```
If we rename val at line 1:

```python
val1 = 1
val = val1 + 1
```

If we rename val at line 2:

```python
val = 1
val1 = val + 1
```

### Sandbox Link

_No response_

### (Only applicable for extension issues) IDE Information

pyrefly==1.1.1
VSCode extension version 1.1.1
Version in mason 1.1.1

No source file, test, or entry point is named. Reproduce the example in VSCode or neovim with pyrefly 1.1.1, then trace the symbol-rename request and its handling of reassigned variables. Done means renaming either occurrence consistently renames all occurrences of the same symbol.

Written by the indexing model from the issue text.