Allow for null in CrashCategory return values

base/src/main/kotlin/de/staropensource/engine/base/implementable/logging/CrashCategory.kt

@@ -68,5 +68,5 @@ interface CrashCategory {
         channelSettings: ChannelSettings?,
         throwable: Throwable?,
         fatal: Boolean,
-    ): LinkedHashMap<String, Any>
+    ): LinkedHashMap<String, Any?>
 }

base/src/main/kotlin/de/staropensource/engine/base/implementable/logging/Filter.kt

@@ -20,12 +20,13 @@
 
 package de.staropensource.engine.base.implementable.logging
 
+import de.staropensource.engine.base.logging.Filterer
 import de.staropensource.engine.base.type.logging.Call
 
 /**
  * Provides methods for filtering log calls.
  *
- * @see de.staropensource.engine.logging.Filterer
+ * @see Filterer
  * @since v1-alpha10
  */
 interface Filter {

base/src/main/kotlin/de/staropensource/engine/base/implementation/logging/crashcategory/InfoCrashCategory.kt

@@ -59,7 +59,7 @@ class InfoCrashCategory private constructor() : CrashCategory {
         channelSettings: ChannelSettings?,
         throwable: Throwable?,
         fatal: Boolean,
-    ): LinkedHashMap<String, Any> {
+    ): LinkedHashMap<String, Any?> {
         return linkedMapOf(
             Pair("Origin", linkedMapOf<String, Any>(
                 Pair("Class", call.origin),

base/src/main/kotlin/de/staropensource/engine/base/logging/CrashHandler.kt

@@ -110,7 +110,9 @@ class CrashHandler private constructor() {
 
                 builder.append("\n${" ".repeat(indent)}-> ${entry}")
 
-                if (map[entry] is LinkedHashMap<*, *>)  // Value is a map
+                if (map[entry] == null)  // Value is null
+                    true
+                else if (map[entry] is LinkedHashMap<*, *>)  // Value is a map
                     builder.append(
                         compileCategory(
                             map[entry] as LinkedHashMap<*, *>,