debugger: Add scrollbars, fix papercuts with completions menu and jumps (#28321)

Closes #ISSUE

Release Notes:

- N/A

crates/debugger_ui/src/session/running/console.rs

@@ -8,7 +8,7 @@ use dap::OutputEvent;
 use editor::{CompletionProvider, Editor, EditorElement, EditorStyle, ExcerptId};
 use fuzzy::StringMatchCandidate;
 use gpui::{Context, Entity, Render, Subscription, Task, TextStyle, WeakEntity};
-use language::{Buffer, CodeLabel};
+use language::{Buffer, CodeLabel, ToOffset};
 use menu::Confirm;
 use project::{
     Completion,
@@ -392,25 +392,61 @@ impl ConsoleQueryBarCompletionProvider {
                 )
             })
         });
-
+        let snapshot = buffer.read(cx).text_snapshot();
         cx.background_executor().spawn(async move {
+            let completions = completion_task.await?;
+
             Ok(Some(
-                completion_task
-                    .await?
-                    .iter()
-                    .map(|completion| project::Completion {
-                        old_range: buffer_position..buffer_position, // TODO(debugger): change this
-                        new_text: completion.text.clone().unwrap_or(completion.label.clone()),
-                        label: CodeLabel {
-                            filter_range: 0..completion.label.len(),
-                            text: completion.label.clone(),
-                            runs: Vec::new(),
-                        },
-                        icon_path: None,
-                        documentation: None,
-                        confirm: None,
-                        source: project::CompletionSource::Custom,
-                        insert_text_mode: None,
+                completions
+                    .into_iter()
+                    .map(|completion| {
+                        let new_text = completion
+                            .text
+                            .as_ref()
+                            .unwrap_or(&completion.label)
+                            .to_owned();
+                        let mut word_bytes_length = 0;
+                        for chunk in snapshot
+                            .reversed_chunks_in_range(language::Anchor::MIN..buffer_position)
+                        {
+                            let mut processed_bytes = 0;
+                            if let Some(_) = chunk.chars().rfind(|c| {
+                                let is_whitespace = c.is_whitespace();
+                                if !is_whitespace {
+                                    processed_bytes += c.len_utf8();
+                                }
+
+                                is_whitespace
+                            }) {
+                                word_bytes_length += processed_bytes;
+                                break;
+                            } else {
+                                word_bytes_length += chunk.len();
+                            }
+                        }
+
+                        let buffer_offset = buffer_position.to_offset(&snapshot);
+                        let start = buffer_offset - word_bytes_length;
+                        let start = snapshot.anchor_before(start);
+                        let old_range = start..buffer_position;
+
+                        project::Completion {
+                            old_range,
+                            new_text,
+                            label: CodeLabel {
+                                filter_range: 0..completion.label.len(),
+                                text: completion.label,
+                                runs: Vec::new(),
+                            },
+                            icon_path: None,
+                            documentation: None,
+                            confirm: None,
+                            source: project::CompletionSource::BufferWord {
+                                word_range: buffer_position..language::Anchor::MAX,
+                                resolved: false,
+                            },
+                            insert_text_mode: None,
+                        }
                     })
                     .collect(),
             ))