navigateTo: Collect results from all referenced projects. (#25283)

* navigateTo: Collect results from all referenced projects.

* Don't use project references, just source maps

* Move more code to session

* Test when implementation file is deleted

* Use tsserver tests instead of fourslash tests to ensure session is used

* Support find-all-references

* Restore fourslash tests

* Update emit baselines (added missing newline)

* Support rename

* @weswigham code review

* Don't open/close files

* Avoid growing `toDo` too eagerly

* @sheetalkamat code review

* Also get symlinked projects for originalLocation

* Update API (#24966)

* More @sheetalkamat code review

* Remove unnecessary test

* Update API (#24966)

src/harness/virtualFileSystemWithWatch.ts

@@ -78,7 +78,9 @@ interface Array<T> {}`
     }
 
     export interface SymLink {
+        /** Location of the symlink. */
         path: string;
+        /** Relative path to the real file. */
         symLink: string;
     }