[ts] Include source content in sourcemaps of es6 module dist files.

spine-ts/tsconfig.base.json

@@ -4,6 +4,7 @@
 		"noImplicitAny": true,
 		"preserveConstEnums": true,
 		"sourceMap": true,
+		"inlineSources": true,
 		"esModuleInterop": true,
 		"lib": [
 			"DOM",