fix: keep lexer plugins inside tag interpolation (#3296)

Author: rhendric

packages/pug-lexer/index.js

@@ -545,6 +545,7 @@ Lexer.prototype = {
         interpolated: true,
         startingLine: this.lineno,
         startingColumn: this.colno,
+        plugins: this.plugins,
       });
       var interpolated;
       try {

packages/pug/test/plugins.test.js

@@ -0,0 +1,18 @@
+const pug = require('../');
+
+test('#3295 - lexer plugins should be used in tag interpolation', () => {
+  const lex = {
+    advance(lexer) {
+      if ('~' === lexer.input.charAt(0)) {
+        lexer.tokens.push(lexer.tok('text', 'twiddle-dee-dee'));
+        lexer.consume(1);
+        lexer.incrementColumn(1);
+        return true;
+      }
+    },
+  };
+  const input = 'p Look at #[~]';
+  const expected = '<p>Look at twiddle-dee-dee</p>';
+  const output = pug.render(input, {plugins: [{lex}]});
+  expect(output).toEqual(expected);
+});