fix: Merge default palette with user palette

book/src/themes.md

@@ -124,7 +124,9 @@ black = "#000000"
 Remember that the `[palette]` table includes all keys after its header,
 so you should define the palette after normal theme options.
 
-If there is no `[palette]` section, a default palette which uses the terminal's default 16 colors are used:
+The default palette uses the terminal's default 16 colors, and the colors names
+are listed below. The `[palette]` section in the config file takes precedence
+over it and is merged into the default palette.
 
 | Color Name      |
 | ---             |

helix-view/src/theme.rs

@@ -143,7 +143,8 @@ struct ThemePalette {
 
 impl Default for ThemePalette {
     fn default() -> Self {
-        Self::new(hashmap! {
+        Self {
+            palette: hashmap! {
                 "black".to_string() => Color::Black,
                 "red".to_string() => Color::Red,
                 "green".to_string() => Color::Green,
@@ -160,13 +161,19 @@ impl Default for ThemePalette {
                 "light-cyan".to_string() => Color::LightCyan,
                 "light-gray".to_string() => Color::LightGray,
                 "white".to_string() => Color::White,
-        })
+            },
+        }
     }
 }
 
 impl ThemePalette {
     pub fn new(palette: HashMap<String, Color>) -> Self {
-        Self { palette }
+        let ThemePalette {
+            palette: mut default,
+        } = ThemePalette::default();
+
+        default.extend(palette);
+        Self { palette: default }
     }
 
     pub fn hex_string_to_rgb(s: &str) -> Result<Color, String> {