docs(guide/compiler): add missing closing parenthesis

Author: n0nick

docs/content/guide/compiler.ngdoc

@@ -325,7 +325,7 @@ This will not render properly, unless we do some scope magic.
 
 The first issue we have to solve is that the dialog box template expects `title` to be defined.
 But we would like the template's scope property `title` to be the result of interpolating the
-`<dialog>` element's `title` attribute (i.e. `"Hello {{username}}"`. Furthermore, the buttons expect
+`<dialog>` element's `title` attribute (i.e. `"Hello {{username}}"`). Furthermore, the buttons expect
 the `onOk` and `onCancel` functions to be present in the scope. This limits the usefulness of the
 widget. To solve the mapping issue we use the `locals` to create local variables which the template
 expects as follows: