Update error message instructions

[ef4]

Since Ember 3.25 it's unnecessary to pass a helper or modifier class to the corresponding template keyword before you can use them. They are first-class values that can be used directly.

This updates the error message to stop suggesting the now-unnecessary use of the helper and modifier keywords.

Before:

Assertion Failed: Passing a dynamic string to the (helper) keyword is disallowed. (You specified (helper s) and s evaluated into "my-helper".) This ensures we can statically analyze the template and determine which helpers are used. If the helper name is always the same, use a string literal instead, i.e. (helper "my-helper"). Otherwise, import the helpers into JavaScript and pass them to the helper keyword. See https://github.com/emberjs/rfcs/blob/master/text/0496-handlebars-strict-mode.md#4-no-dynamic-resolution for details. ('sample2/templates/application.hbs' @ L3:C9)

After:

Assertion Failed: Passing a dynamic string to the (helper) keyword is disallowed. (You specified (helper s) and s evaluated into "my-helper".) This ensures we can statically analyze the template and determine which helpers are used. If the helper name is always the same, use a string literal instead, i.e. (helper "my-helper"). Otherwise, import the helpers into JavaScript and pass them directly. See https://github.com/emberjs/rfcs/blob/master/text/0496-handlebars-strict-mode.md#4-no-dynamic-resolution for details. ('sample2/templates/application.hbs' @ L3:C9)

[locks]

Thanks!