Add Angular 21.2 template syntax: instanceof operator and arrow functions

[Copilot]

Angular 21.2 introduced two new template expression features: the instanceof binary operator and arrow function support. This PR adds syntax highlighting for both.

Changes

• instanceof operator — added to ng-operators alongside typeof/void, scoped as keyword.operator.type.ngx
• Arrow function => — scoped as keyword.declaration.function.arrow.ngx; arrow function parameters are scoped as variable.parameter.ngx for both single-param (item => ...) and grouped-params ((x) => ..., (x, y) => ...) forms using a look-ahead for single-param and a branch mechanism for grouped-params (with fallback to regular group handling if not followed by =>)

Examples

{{ obj instanceof SomeClass }}

{{ items.filter(item => item.active) }}

{{ (x) => x * 2 }}

Tests added for all three cases in tests/syntax_test_scopes.component.html.

Original prompt

support new syntax addition in angular 21.2

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[princemaple]

@copilot address reviews

[Copilot]

@copilot address reviews

Done in c248aa4. Two changes:

• => is now scoped as keyword.declaration.function.arrow.ngx
• Arrow function parameters are now scoped as variable.parameter.ngx for both single-param (item => ...) and grouped-params ((x) => ..., (x, y) => ...) forms — using a look-ahead for single-param and a branch mechanism for grouped-params (with fallback to regular group handling if not followed by =>)

[princemaple]

Hi @deathaxe thanks for the early review. Really appreciate it. Do you have more to add? I will merge with your approval.