Make initial editing mode configurable

ref: helix-editor/helix#3366

Co-authored-by: JJ <git@toki.la>

book/src/configuration.md

@@ -69,6 +69,7 @@ Its settings will be merged with the configuration directory `config.toml` and t
 | `popup-border` | Draw border around `popup`, `menu`, `all`, or `none` | `none` |
 | `indent-heuristic` | How the indentation for a newly inserted line is computed: `simple` just copies the indentation level from the previous line, `tree-sitter` computes the indentation based on the syntax tree and `hybrid` combines both approaches. If the chosen heuristic is not available, a different one will be used as a fallback (the fallback order being `hybrid` -> `tree-sitter` -> `simple`). | `hybrid`
 | `jump-label-alphabet` | The characters that are used to generate two character jump labels. Characters at the start of the alphabet are used first. | `"abcdefghijklmnopqrstuvwxyz"`
+| `initial-mode` | The initial mode for newly opened editors. | `"normal"` |
 
 ### `[editor.statusline]` Section
 

helix-view/src/editor.rs

@@ -351,6 +351,8 @@ pub struct Config {
     pub jump_label_alphabet: Vec<char>,
     /// Explorer configuration.
     pub explorer: ExplorerConfig,
+    /// The initial mode for newly opened editors. Defaults to `"normal"`.
+    pub initial_mode: Mode,
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, Eq, PartialOrd, Ord)]
@@ -929,6 +931,7 @@ impl Default for Config {
             indent_heuristic: IndentationHeuristic::default(),
             jump_label_alphabet: ('a'..='z').collect(),
             explorer: ExplorerConfig::default(),
+            initial_mode: Mode::Normal,
         }
     }
 }
@@ -1504,7 +1507,8 @@ impl Editor {
             return;
         }
 
-        self.enter_normal_mode();
+        // this causes tree.rs to panic upon launch. todo: debug
+        // self.enter_normal_mode();
 
         match action {
             Action::Replace => {
@@ -1593,6 +1597,7 @@ impl Editor {
 
     /// Generate an id for a new document and register it.
     fn new_document(&mut self, mut doc: Document) -> DocumentId {
+        self.mode = self.config().initial_mode;
         let id = self.next_document_id;
         // Safety: adding 1 from 1 is fine, probably impossible to reach usize max
         self.next_document_id =