Switch libReplacement to false by default #62214

In TypeScript 5.8, we introduced the libReplacement. This flag toggled whether or not TypeScript actually looked for libraries via node_modules/@typescript/lib-*

For example, if you have "lib": ["es2015", "dom"] in your settings, TypeScript would try to resolve @typescript/lib-es2015 and @typescript/lib-dom from node_modules and load their contents. However, this resolution happened regardless of whether you were using the functionality, and libReplacement lets you opt out.

In TypeScript 7.0 (the native preview), we've ported libReplacement to be false by default.

TypeScript 6.0 will change the default to false to align with TypeScript 7.0

See more similar discussions around 6.0/7.0 changes at #54500.