docs(ui): note treesitter syntax highlights in stack preview

Author: mhiro2

README.md

@@ -24,7 +24,7 @@ peekstack.nvim focuses on preserving the _trail_ of your exploration.
 ### Core
 
 - 🧭 **Peek stack UI**: stack / cascade / single layouts
-- 🧱 **Stack view**: list popups, focus, pin, rename, reorder, history
+- 🧱 **Stack view**: list popups, focus, pin, rename, reorder, history, preview syntax highlights
 - 🔍 **Providers**: LSP / diagnostics / file / marks
 - 🚀 **Promote**: fast split/tab promotion
 - 🧷 **Inline + quick peek**: inline preview or ephemeral popups
@@ -42,7 +42,7 @@ peekstack.nvim focuses on preserving the _trail_ of your exploration.
 - Neovim ≥ 0.10
 - `rg` (only if you use `grep.search`)
 - Optional: `telescope.nvim` / `fzf-lua` / `snacks.nvim` (if you switch picker backends)
-- Optional: Tree-sitter parsers (if you enable `ui.title.context`; Neovim bundles the runtime, but parsers are separate)
+- Optional: Tree-sitter parsers (for `ui.title.context` and stack view preview syntax highlighting; Neovim bundles the runtime, but parsers are separate)
 
 ## 🚀 Installation
 

doc/peekstack.txt

@@ -161,6 +161,7 @@ Commands are registered after `setup()` is called.
     Open the stack view panel listing all active popups.
     The focused popup is highlighted with a `▶` marker.
     Each entry shows a preview line of the source code below it.
+    Preview lines use Tree-sitter based syntax highlights when available.
 
 :PeekstackSaveSession                        *:PeekstackSaveSession*
     Save the current popup stack to disk (requires persist.enabled = true).
@@ -409,7 +410,7 @@ Stack view highlights:
     PeekstackStackViewIcon         Provider icon (links to Special)
     PeekstackStackViewLine         Line number (links to LineNr)
     PeekstackStackViewFocused      Focused entry marker (links to Type)
-    PeekstackStackViewPreview      Preview line text (links to Comment)
+    PeekstackStackViewPreview      Preview line base text (links to Comment)
     PeekstackStackViewFilter       Filter header (links to Search)
     PeekstackStackViewHeader       Stack header (links to Title)
     PeekstackStackViewEmpty        Empty state text (links to Comment)