feat: add configurable whitespace markers

src/editor.rs

@@ -1764,6 +1764,7 @@ pub struct Editor {
     labels: BTreeMap<String, String>,
     scroll_distance: Option<usize>,
     highlight_trailing_whitespace: bool,
+    whitespace_characters: BTreeMap<char, char>,
     battery_charge: Option<u8>,
     battery_label: String,
     git_blame: bool,
@@ -1867,6 +1868,7 @@ impl Editor {
             labels: BTreeMap::new(),
             scroll_distance: Some(0),
             highlight_trailing_whitespace: false,
+            whitespace_characters: BTreeMap::new(),
             battery_charge: None,
             battery_label: String::new(),
             git_blame: true,
@@ -2621,6 +2623,14 @@ impl Editor {
         self.highlight_trailing_whitespace = enabled;
     }
 
+    pub(crate) fn whitespace_characters(&self) -> &BTreeMap<char, char> {
+        &self.whitespace_characters
+    }
+
+    pub(crate) fn set_whitespace_characters(&mut self, characters: BTreeMap<char, char>) {
+        self.whitespace_characters = characters;
+    }
+
     pub(crate) fn set_diff_context_options(&mut self, context_lines: usize, expand_lines: usize) {
         self.diff_context_options = (context_lines, expand_lines);
         if let Some(diff) = &mut self.diff {