Fix nullability warning

Author: GlassBricks

generator/types.ts

@@ -901,7 +901,7 @@ function isNullableFromDescription(
   parent: string,
 ): boolean {
   const nullableRegex =
-    /(specify|passing|returns?|or|be|possibly|otherwise|else|writing|set(ting)?(( this)?|( the name)?)( to)?) [`']?nil[`']?|`?nil`? (if|when|otherwise|erases|is returned)/i
+    /(specify|passing|returns?|or|be|possibly|otherwise|else|writing|set(ting)?(( this)?|( the name)?)( to)?|read as) [`']?nil[`']?|`?nil`? (if|when|otherwise|erases|is returned)/i
   const nullable = member.description.match(nullableRegex)
   if (nullable) {
     if (!member.description.match(/[`' ]nil/i)) {

runtime/generated/classes.d.ts

@@ -23263,7 +23263,7 @@ declare module "factorio:runtime" {
      * @param index The index of the mapper to read.
      * @see {@link https://lua-api.factorio.com/2.0.54/classes/LuaRecord.html#get_mapper Online documentation}
      */
-    get_mapper(index: uint, type: "from" | "to"): UpgradeMapperSource | UpgradeMapperDestination
+    get_mapper(index: uint, type: "from" | "to"): UpgradeMapperSource | UpgradeMapperDestination | nil
     /**
      * Sets the module filter at the given index for this upgrade item.
      *
@@ -23887,7 +23887,7 @@ declare module "factorio:runtime" {
      * @param index The index of the mapper to read.
      * @see {@link https://lua-api.factorio.com/2.0.54/classes/LuaRecord.html#get_mapper Online documentation}
      */
-    get_mapper(index: uint, type: "from" | "to"): UpgradeMapperSource | UpgradeMapperDestination
+    get_mapper(index: uint, type: "from" | "to"): UpgradeMapperSource | UpgradeMapperDestination | nil
     /**
      * Sets the module filter at the given index for this upgrade item.
      *