docs(http): Remove extra semicolons in the http guide (#37228)

An extra semicolon in searchHeroes function was removed in the http guide
found in aio/content/guide/http.md

docs(http): Remove extra semicolon in a code example found in the http guide

Removed extra semicolon in handleError function in the file located at
aio/content/examples/http/src/app/config/config.service.ts, which serves
as a source of code examples for the http guide.

Replace a comma for a dot in the comment at line 79 to ensure consistency
with the rest of the document.

Capitalized and added a dot at the end of the comment at line 84 to
ensure consistency with the other comments.

PR Close #37228

aio/content/guide/http.md

@@ -277,7 +277,7 @@ searchHeroes(term: string): Observable {
   return this.http.jsonp(heroesUrl, 'callback').pipe(
       catchError(this.handleError('searchHeroes', [])) // then handle the error
     );
-};
+}
 ```
 
 This request passes the `heroesURL` as the first parameter and the callback function name as the second parameter.