Improve how go-to-definition behaves for Wasp SDK

[sodic]

We want the Ctrl+click (go to definition) command to take the user to the symbol's definition inside a source file (TypeScript).

What happens instead:

• For type definitions, we take them to the .d.ts files in dist.
• For value definitions, we take them to .js files in dist.
• When navigating the code inside our SDK, we take them to .js for both types and values. This is especially confusing since the types don't exist in .js files.

What we want to happen:

• No matter where they are (their code or our SDK), for both types and values, we take them to the .ts file in src.

Check the tanstack packages to see how it's done.

[!NOTE] I believe this was working after 0.12.0. It was possibly broken during the fixing effort. However takes on this issue, please check whether this is right so we know what to prevent.

[sodic]

Idea: This might be fixable with "declarationMap": true in TS config. Sources:

• https://www.typescriptlang.org/tsconfig/#declarationMap
• https://www.totaltypescript.com/tsconfig-cheat-sheet