[lezer] Allow slash in bibtex identifier

GitOrigin-RevId: 88f5cf069563940b1e42763babdc1e58d65c1d31

services/web/frontend/js/features/source-editor/lezer-bibtex/bibtex.grammar

@@ -4,7 +4,7 @@
 
 @tokens {
   whiteSpace { @whitespace+ }
-  Identifier { $[a-zA-Z:_0-9-]+ }
+  Identifier { $[a-zA-Z:_0-9-/]+ }
   StringName { $[a-zA-Z:_] $[a-zA-Z:_0-9-]* }
   FieldName {$[a-zA-Z-_0-9]+}
   LiteralString {