Add underscore separator to field names

This allows us to distinguish between aClass1_23 and aClass12_3, for
example.

deob/src/main/java/dev/openrs2/deob/remap/TypedRemapper.kt

@@ -86,7 +86,8 @@ class TypedRemapper private constructor(
         }
 
         private fun generateName(prefixes: MutableMap<String, Int>, prefix: String): String {
-            return prefix + prefixes.merge(prefix, 1, Integer::sum)
+            val separator = if (prefix.last().isDigit()) { "_" } else { "" }
+            return prefix + separator + prefixes.merge(prefix, 1, Integer::sum)
         }
 
         private fun createClassMapping(classes: List<ClassMetadata>): Map<String, String> {