fix multiple includes per chat

previously, putting everything into a "changeset" first (where each item
says "replace line X with the following block") and applying the
changeset after collecting all changes would lead to wrong line numbers,
since inserting a block will move all lines down by some amount.

Gotta replace the include-line with the block right away before you move
on to following include lines.

This was so complex in the first place to please rust's borrow checker.

src/chat.rs

@@ -202,31 +202,37 @@ impl ChatDB {
         sequence: &mut Value,
         include_db: &HashMap<String, Vec<Value>>,
     ) {
-        let mut changes: Vec<(usize, String)> = Vec::new();
         if let Some(vector) = sequence.as_sequence_mut() {
-            for (index, item) in vector.iter_mut().enumerate() {
+            let mut index = 0;
+            loop {
+                // this loop seems unnecessarily convoluted, but I had to write it
+                // this way to make rust's borrow checker happy.
+                let item_maybe = vector.get(index);
+                let item = if let Some(item) = item_maybe {
+                    item.clone()
+                } else {
+                    break;
+                };
                 match item {
-                    Value::Mapping(map) => {
-                        for (key, value) in map.iter_mut() {
+                    Value::Mapping(mut map) => {
+                        for (key, value) in map.clone().iter() {
                             if let (Some(key), Some(value)) = (key.as_str(), value.as_str()) {
+                                let label = value.to_string();
                                 if key == TOKEN_INCLUDE {
-                                    changes.push((index, value.to_string()));
+                                    vector.remove(index);
+                                    if let Some(chat) = include_db.get(&label) {
+                                        vector.splice(index..index, chat.iter().cloned());
+                                    }
                                 }
                             } else if value.is_sequence() {
+                                let value = map.get_mut(key).unwrap();
                                 ChatDB::preprocess_includes_recursively(value, include_db);
                             }
                         }
                     }
                     _ => {}
                 }
-            }
-            for (index, label) in changes {
-                if index < vector.len() {
-                    vector.remove(index);
-                    if let Some(chat) = include_db.get(&label) {
-                        vector.splice(index..index, chat.iter().cloned());
-                    }
-                }
+                index += 1;
             }
         }
     }
@@ -946,6 +952,10 @@ pub fn update_chat_variables(
     q_player: Query<&actor::Suit, With<actor::Player>>,
 ) {
     if let Ok(suit) = q_player.get_single() {
-        vars.set_in_scope("$", "player_oxygen_seconds", (suit.oxygen / nature::OXY_S).to_string());
+        vars.set_in_scope(
+            "$",
+            "player_oxygen_seconds",
+            (suit.oxygen / nature::OXY_S).to_string(),
+        );
     }
 }