Remove IMPL_OBJ_START from IDENTIFIER definition

spec/src/main/asciidoc/ELSpec.adoc

diff --git a/spec/src/main/asciidoc/ELSpec.adoc b/spec/src/main/asciidoc/ELSpec.adoc
index 0d7f250..bba00f2 100644
--- a/spec/src/main/asciidoc/ELSpec.adoc
+++ b/spec/src/main/asciidoc/ELSpec.adoc
@@ -2166,8 +2166,7 @@
 |   < CONCAT : "+=" >
 |   < ASSIGN : "=" >
 |   < ARROW : "->" >
-|   < IDENTIFIER : (<LETTER>|<IMPL_OBJ_START>) (<LETTER>|<DIGIT>)* >
-|   < #IMPL_OBJ_START: "#" >
+|   < IDENTIFIER : <LETTER> (<LETTER>|<DIGIT>)* >
 |   < #LETTER:
         [
         "\u0024",