fix(lsp): preserve URL extensions in typeof import(...) hovers (#34565)

## Summary

When hovering over a value whose type is a remote module namespace,
vscode displayed `typeof import('https://.../mod')` instead of the URL
the user actually wrote (`typeof import('https://.../mod.ts')`).

The cause was that the LSP's custom document registry
(`cli/tsc/98_lsp.js`) built source files via
`ts.createLanguageServiceSourceFile` but never set
`sourceFile.moduleName`. Without `moduleName`, tsc's
`getSpecifierForModuleSymbol` falls through to `getModuleSpecifiers`,
which strips `.ts` from URL specifiers.

The CLI path (`cli/tsc/97_ts_host.js`) already sets `moduleName =
specifier` after creating a source file, so this only affects the LSP.

Mirror that behavior on the LSP side by assigning `moduleName` in both
`acquireDocumentWithKey` and `updateDocumentWithKey`, but only for
non-`file:` specifiers. Skipping `file:` keeps tsc's relative-path
computation for local files and prevents the internal `/$node_modules/`
rewrite from leaking into hovers for npm packages.

Fixes #16058.

Closes denoland/orchid#320

## Test plan

- [x] `cargo test -p deno --lib lsp::tsc::tests` — the existing
`test_modify_sources` already exercises this exact code path through a
`Property X does not exist on type 'typeof import("URL")'` diagnostic;
its expected message is updated to keep `.ts`.
- [x] Outdated comment block in `display_parts_to_string` that
documented the stripped-extension behavior as a tsc limitation has been
removed (#16058 is fixed).

Co-authored-by: divybot <divybot@users.noreply.github.com>
Co-authored-by: Divy Srivastava <me@littledivy.com>

Author: divybot

cli/lsp/tsc.rs

@@ -2076,36 +2076,6 @@ fn display_parts_to_string<'a>(
         // should decode percent-encoding string when hovering over the right edge of module specifier like below
         // module "file:///path/to/🦕"
         to_percent_decoded_str(&part.text),
-        // NOTE: The reason why an example above that lacks `.ts` extension is caused by the implementation of tsc itself.
-        // The request `tsc.request.getQuickInfoAtPosition` receives the payload from tsc host as follows.
-        // {
-        //   text_span: {
-        //     start: 19,
-        //     length: 9,
-        //   },
-        //   displayParts:
-        //     [
-        //       {
-        //         text: "module",
-        //         kind: "keyword",
-        //         target: null,
-        //       },
-        //       {
-        //         text: " ",
-        //         kind: "space",
-        //         target: null,
-        //       },
-        //       {
-        //         text: "\"file:///path/to/%F0%9F%A6%95\"",
-        //         kind: "stringLiteral",
-        //         target: null,
-        //       },
-        //     ],
-        //   documentation: [],
-        //   tags: null,
-        // }
-        //
-        // related issue: https://github.com/denoland/deno/issues/16058
       ),
     }
   }
@@ -6578,7 +6548,7 @@ mod tests {
             "line": 2,
             "character": 17
           },
-          "messageText": "Property \'a\' does not exist on type \'typeof import(\"https://deno.land/x/example/a\", { with: { \"resolution-mode\": \"import\" } })\'.",
+          "messageText": "Property \'a\' does not exist on type \'typeof import(\"https://deno.land/x/example/a.ts\", { with: { \"resolution-mode\": \"import\" } })\'.",
           "sourceLine": "          if (a.a === \"b\") {",
           "fileName": specifier,
         }

cli/tsc/98_lsp.js

@@ -42,6 +42,22 @@ function getCompilationSettings(settingsOrHost) {
   return /** @type {ts.CompilerOptions} */ (settingsOrHost);
 }
 
+/**
+ * Assigns `moduleName` on a source file so that tsc displays the original
+ * module specifier (e.g. in `typeof import("...")`) for non-file URL
+ * specifiers like `https://...`. For `file://` specifiers we leave it
+ * unset so tsc keeps its usual relative-path computation and so internal
+ * details like the `/$node_modules/` rewrite don't leak into hovers.
+ *
+ * @param {ts.SourceFile} sourceFile
+ * @param {string} fileName
+ */
+function setSourceFileModuleNameForDisplay(sourceFile, fileName) {
+  if (!fileName.startsWith("file:")) {
+    sourceFile.moduleName = fileName;
+  }
+}
+
 // We need to use a custom document registry in order to provide source files
 // with an impliedNodeFormat to the ts language service
 
@@ -105,6 +121,12 @@ const documentRegistry = {
       if (scriptSnapshot.isClassicScript) {
         sourceFile.externalModuleIndicator = undefined;
       }
+      // Preserve the original module specifier so that `typeof import(...)`
+      // displays the URL exactly as the user wrote it, including extensions.
+      // Without this, tsc's `getSpecifierForModuleSymbol` recomputes the
+      // specifier via `getModuleSpecifiers`, which strips `.ts` from URL
+      // imports like `https://example.com/mod.ts`. See denoland/deno#16058.
+      setSourceFileModuleNameForDisplay(sourceFile, fileName);
       documentRegistrySourceFileCache.set(mapKey, sourceFile);
     }
     const sourceRefCount = SOURCE_REF_COUNTS.get(fileName) ?? 0;
@@ -170,6 +192,7 @@ const documentRegistry = {
       if (scriptSnapshot.isClassicScript) {
         sourceFile.externalModuleIndicator = undefined;
       }
+      setSourceFileModuleNameForDisplay(sourceFile, fileName);
       documentRegistrySourceFileCache.set(mapKey, sourceFile);
     }
     return sourceFile;