### Godot version

v4.0.stable.official [92bee43ad]

### System information

Steam OS Holo, Steam Deck

### Issue description

Using a `[br]` tag at the end of a line in a documentation comment adds an additional space at the beginning of the following line:

![image](https://user-images.githubusercontent.com/857660/236700815-c78a317f-cdf8-4f3c-8489-41f9559ffe6d.png)


### Steps to reproduce

The script below is what I used to generate the image above:

```gdscript
class_name Test
extends Node

## High-level description
##
## First line of detail.[br]
## Second line of detail.
```

Removing the space between `##` and `Second` doesn't change the output.

The only workaround I've found so far is to remove the linebreak after the `[br]` tag, but this makes the documentation comments harder to read in the editor:

```gdscript
class_name Test
extends Node

## High-level description
##
## First line of detail.[br]Second line of detail.
```

### Minimal reproduction project

N/A
clear();
	String source = p_source_code;
	int cursor_line = -1;
	int cursor_column = -1;
	for_completion = p_for_completion;
	int tab_size = 4;
#ifdef TOOLS_ENABLED
	if (EditorSettings::get_singleton()) {
		tab_size = EditorSettings::get_singleton()->get_setting("text_editor/behavior/indent/size");
	}
#endif 
	if (p_for_completion) {
		
		const Vector<String> lines = p_source_code.split("\n");
		cursor_line = 1;
		cursor_column = 1;
		for (int i = 0; i < lines.size(); i++) {
			bool found = false;
			const String &line = lines[i];
			for (int j = 0; j < line.size(); j++) {
				if (line[j] == char32_t(0xFFFF)) {
					found = true;
					break;
				} else if (line[j] == '\t') {
					cursor_column += tab_size - 1;
				}
				cursor_column++;
			}