Fixed PHPstan detections.

phpstan.neon

@@ -1,9 +1,37 @@
 parameters:
   level: 5
   paths:
+    - database
     - src
+    - public
+    - public-legacy
   bootstrapFiles:
     - misuzu.php
   dynamicConstantNames:
     - MSZ_CLI
     - MSZ_DEBUG
+  ignoreErrors:
+    -
+      identifier: variable.undefined
+      path: public-legacy/forum/posting.php
+    -
+      identifier: variable.undefined
+      path: public-legacy/forum/topic.php
+    -
+      identifier: variable.undefined
+      path: public-legacy/manage/changelog/tag.php
+    -
+      identifier: variable.undefined
+      path: public-legacy/manage/news/category.php
+    -
+      identifier: variable.undefined
+      path: public-legacy/manage/news/post.php
+    -
+      identifier: variable.undefined
+      path: public-legacy/manage/users/note.php
+    -
+      identifier: empty.offset
+      path: public-legacy/search.php
+    -
+      identifier: offsetAccess.notFound
+      path: public-legacy/search.php