feat(language-service): module definitions on directive hover (#32763)

Adds information about the NgModule a Directive is declared in when the
Directive class name is hovered over, in the form

```
(directive) NgModule.Directive: class
```

Closes #32565

PR Close #32763

packages/language-service/src/hover.ts

@@ -9,10 +9,14 @@
 import * as ts from 'typescript';
 import {AstResult} from './common';
 import {locateSymbol} from './locate_symbol';
+import {TypeScriptServiceHost} from './typescript_host';
+import {findTightestNode} from './utils';
 
 // Reverse mappings of enum would generate strings
 const SYMBOL_SPACE = ts.SymbolDisplayPartKind[ts.SymbolDisplayPartKind.space];
 const SYMBOL_PUNC = ts.SymbolDisplayPartKind[ts.SymbolDisplayPartKind.punctuation];
+const SYMBOL_CLASS = ts.SymbolDisplayPartKind[ts.SymbolDisplayPartKind.className];
+const SYMBOL_TEXT = ts.SymbolDisplayPartKind[ts.SymbolDisplayPartKind.text];
 
 /**
  * Traverse the template AST and look for the symbol located at `position`, then
@@ -51,3 +55,66 @@ export function getHover(info: AstResult, position: number): ts.QuickInfo|undefi
     ],
   };
 }
+
+/**
+ * Get quick info for Angular semantic entities in TypeScript files, like Directives.
+ * @param sf TypeScript source file an Angular symbol is in
+ * @param position location of the symbol in the source file
+ * @param host Language Service host to query
+ */
+export function getTsHover(
+    sf: ts.SourceFile, position: number, host: Readonly<TypeScriptServiceHost>): ts.QuickInfo|
+    undefined {
+  const node = findTightestNode(sf, position);
+  if (!node) return;
+  switch (node.kind) {
+    case ts.SyntaxKind.Identifier:
+      return getDirectiveModule(node as ts.Identifier, host);
+    default:
+      break;
+  }
+  return undefined;
+}
+
+/**
+ * Attempts to get quick info for the NgModule a Directive is declared in.
+ * @param directive identifier on a potential Directive class declaration
+ * @param host Language Service host to query
+ */
+function getDirectiveModule(
+    directive: ts.Identifier, host: Readonly<TypeScriptServiceHost>): ts.QuickInfo|undefined {
+  if (!ts.isClassDeclaration(directive.parent)) return;
+  const directiveName = directive.text;
+  const directiveSymbol = host.getStaticSymbol(directive.getSourceFile().fileName, directiveName);
+  if (!directiveSymbol) return;
+
+  const analyzedModules = host.getAnalyzedModules(false);
+  const ngModule = analyzedModules.ngModuleByPipeOrDirective.get(directiveSymbol);
+  if (!ngModule) return;
+
+  const moduleName = ngModule.type.reference.name;
+  return {
+    kind: ts.ScriptElementKind.classElement,
+    kindModifiers:
+        ts.ScriptElementKindModifier.none,  // kindModifier info not available on 'ng.Symbol'
+    textSpan: {
+      start: directive.getStart(),
+      length: directive.end - directive.getStart(),
+    },
+    // This generates a string like '(directive) NgModule.Directive: class'
+    // 'kind' in displayParts does not really matter because it's dropped when
+    // displayParts get converted to string.
+    displayParts: [
+      {text: '(', kind: SYMBOL_PUNC},
+      {text: 'directive', kind: SYMBOL_TEXT},
+      {text: ')', kind: SYMBOL_PUNC},
+      {text: ' ', kind: SYMBOL_SPACE},
+      {text: moduleName, kind: SYMBOL_CLASS},
+      {text: '.', kind: SYMBOL_PUNC},
+      {text: directiveName, kind: SYMBOL_CLASS},
+      {text: ':', kind: SYMBOL_PUNC},
+      {text: ' ', kind: SYMBOL_SPACE},
+      {text: ts.ScriptElementKind.classElement, kind: SYMBOL_TEXT},
+    ],
+  };
+}