Update dependency @angular/language-server to v21 (#154)

* Update dependency @angular/language-server to v21

* update settings to use the latest changes

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Предраг Николић <idmpepe@gmail.com>

Author: renovate[bot]

server/package-lock.json

@@ -2,7 +2,7 @@
   "name": "sublime-ngls",
   "version": "1.0.0",
   "dependencies": {
-    "@angular/language-server": "^20.2.2",
+    "@angular/language-server": "^21.0.0",
     "typescript": "^5.9.2"
   }
 }

server/package.json

@@ -39,7 +39,7 @@
                                         "angular.enable-strict-mode-prompt": {
                                             "type": "boolean",
                                             "default": true,
-                                            "markdownDescription": "Prompt to enable the [strictTemplates](https://angular.dev/reference/configs/angular-compiler-options#stricttemplates) flag in [angularCompilerOptions](https://angular.dev/reference/configs/angular-compiler-options). Note that strict mode is only available when using Ivy."
+                                            "markdownDescription": "Prompt to enable the [strictTemplates](https://angular.dev/reference/configs/angular-compiler-options#stricttemplates) flag in [angularCompilerOptions](https://angular.dev/reference/configs/angular-compiler-options)."
                                         },
                                         "angular.suggest.includeAutomaticOptionalChainCompletions": {
                                             "type": "boolean",