build(docs): fix description comments sometimes empty (#12885)

Follow-up commit for 4879dc4.

---

Disables concatenation of multiple leading comments for a TypeScript node. Since all shipped source files have a license banner at top, the license banner comment would be incorrectly considered as "comment" for the first TypeScript node of a given file. Since there are various files in the Material project where the first node of a source file is exported and should only use the first leading comment, we need to disable comment concatenation.

See for example: https://github.com/angular/material2/blob/master/src/cdk/coercion/boolean-property.ts

Author: devversion

package-lock.json

@@ -72,7 +72,7 @@
     "chalk": "^1.1.3",
     "codelyzer": "^4.3.0",
     "dgeni": "^0.4.10",
-    "dgeni-packages": "^0.26.2",
+    "dgeni-packages": "^0.26.7",
     "firebase": "^4.0.0",
     "firebase-admin": "^5.0.0",
     "firebase-tools": "^4.1.0",

package.json

@@ -1,4 +1,5 @@
 import {Package} from 'dgeni';
+import {Host} from 'dgeni-packages/typescript/services/ts-host/host';
 import {patchLogService} from './patch-log-service';
 import {DocsPrivateFilter} from './processors/docs-private-filter';
 import {Categorizer} from './processors/categorizer';
@@ -124,6 +125,16 @@ apiDocsPackage.config((readTypeScriptModules: ReadTypeScriptModules, tsParser: T
   ];
 });
 
+apiDocsPackage.config((tsHost: Host) => {
+  // Disable concatenation of multiple leading comments for a TypeScript node. Since all shipped
+  // source files have a license banner at top, the license banner comment would be incorrectly
+  // considered as "comment" for the first TypeScript node of a given file. Since there are
+  // various files in the Material project where the first node of a source file is exported and
+  // should only use the first leading comment, we need to disable comment concatenation.
+  // See for example: src/cdk/coercion/boolean-property.ts
+  tsHost.concatMultipleLeadingComments = false;
+});
+
 // Configure processor for finding nunjucks templates.
 apiDocsPackage.config((templateFinder: any, templateEngine: any) => {
   // Where to find the templates for the doc rendering