chore: revert new on Scrollable

but due to limitation of rustc
rust-lang/rust#20400
we can't have two new functions based on non-overlapping associated types

Author: zjp-CN

src/bin/ui/scrollable/markdown/mod.rs

@@ -1,4 +1,5 @@
 use super::Scrollable;
+use crate::Result;
 use ratatui::layout::Rect;
 use std::{fmt, ops::Deref};
 use term_rustdoc::tree::Text as StyledText;
@@ -44,3 +45,14 @@ impl StyledLines {
         parse::md(doc)
     }
 }
+
+impl ScrollText {
+    pub fn new_text(doc: &str, area: Rect) -> Result<Self> {
+        // TODO:max_windth and text wrap for markdown
+        Ok(Scrollable {
+            lines: StyledLines::new(doc),
+            area,
+            ..Default::default()
+        })
+    }
+}

src/bin/ui/scrollable/mod.rs

@@ -60,25 +60,22 @@ impl<Lines: Default> Default for Scrollable<Lines> {
     }
 }
 
-impl<Lines: Deref<Target = [TreeLine]>> Scrollable<Lines> {
-    pub fn new(lines: Lines, full: Rect) -> Result<Self> {
+impl<Lines: Default + Deref<Target = [TreeLine]>> Scrollable<Lines> {
+    pub fn new(lines: Lines, area: Rect) -> Result<Self> {
         let w = lines.as_ref().iter().map(TreeLine::width).max();
         let max_windth = w.ok_or_else(|| err!("The documentation is empty with no items."))?;
-        if full.width < max_windth {
+        if area.width < max_windth {
             warn!(
-                full.width,
+                area.width,
                 max_windth, "Outline width exceeds the area width, so lines may be truncated."
             );
         }
 
-        let (start, cursor, select) = Default::default();
         Ok(Self {
             lines,
             max_windth,
-            area: full,
-            start,
-            cursor,
-            select,
+            area,
+            ..Default::default()
         })
     }
 }