`[br][br]` in docstring is not rendered properly in the hover widget

### Godot version

v4.8.dev3.official [51105ccbe]

### VS Code version

1.132.0

### Godot Tools VS Code extension version

2.7.1

### System information

macOS 15.7.7

### Issue description

In Godot docstring, `[br][br]` is not rendered as an empty new line, and it is omitted.

For example:

```gdscript
## Some sentences.[br][br]
##
## Some sentences.[br][br]
##
## Some sentences but only one br.[br]
##
## Some sentences.[br][br]
##
## Some sentences.[br][br]
func sometest():
pass
```

It will generate hover widget like this:

`[br]` is not affected and it is rendered normally, while `[br][br]` is omitted.

In Godot, it will be rendered like this:

### Steps to reproduce

1. Paste this code to any script file and hover onto the method name:

```gdscript
## Some sentences.[br][br]
##
## Some sentences.[br][br]
##
## Some sentences but only one br.[br]
##
## Some sentences.[br][br]
##
## Some sentences.[br][br]
func sometest():
pass
```

2. Observe the result.

PS: I am happy to provide a PR to fix it (after this issue is considered as a bug and should be fixed).

No source file or test is named in the issue. Start by reproducing the example in a Godot script and tracing the VS Code extension's hover-widget documentation rendering, then locate the handling for consecutive [br] tags. Done means [br] still renders normally and [br][br] produces the empty line shown by Godot.

Written by the indexing model from the issue text.