lib/search/word_search: use map comprehensions

lib/search/word_search/regrouping.dart

@@ -184,18 +184,15 @@ GroupedWordResult _regroup_words({
 
   return GroupedWordResult(
     rubys: rubys,
-    readingInfos: Map.fromEntries(
-      readingElementInfos.map((e) => MapEntry(
-            e['reading'] as String,
-            JMdictReadingInfo.fromId(e['info'] as String),
-          )),
-    ),
-    kanjiInfos: Map.fromEntries(
-      kanjiElementInfos.map((e) => MapEntry(
-            e['reading'] as String,
-            JMdictKanjiInfo.fromId(e['info'] as String),
-          )),
-    ),
+    readingInfos: {
+      for (final rei in readingElementInfos)
+        rei['reading'] as String:
+            JMdictReadingInfo.fromId(rei['info'] as String),
+    },
+    kanjiInfos: {
+      for (final kei in kanjiElementInfos)
+        kei['reading'] as String: JMdictKanjiInfo.fromId(kei['info'] as String),
+    },
   );
 }