ref: remove old docs variant

docs/ru/reference/grammar_ebnf.md

@@ -1,33 +1,2 @@
 # Грамматика (EBNF)
 
-Упрощённая грамматика текущего парсера:
-
-```
-program        = { statement } ;
-statement      = class | function | if | block | return | expression ";" ;
-block          = "{" { statement } "}" ;
-class          = "class" name "{" { declaration | function } "}" ;
-function       = "fn" name "(" [ parameters ] ")" [ type-name ] statement ;
-parameters     = parameter { "," parameter } ;
-parameter      = type-name name ;
-return         = "return" [ expression ] ";" ;
-if             = "if" "(" expression ")" statement [ "else" statement ] ;
-expression     = assignment ;
-assignment     = new-expression [ "=" assignment ] ;
-new-expression = logical-or | "new" name ;
-logical-or     = logical-and { "||" logical-and } ;
-logical-and    = comparison { "&&" comparison } ;
-comparison     = term { compare-op term } ;
-term           = factor { ( "+" | "-" ) factor } ;
-factor         = power { ( "*" | "/" | "%" ) power } ;
-power          = unary [ "^" unary ] ;
-unary          = ( "+" | "-" | "!" ) unary | postfix ;
-postfix        = primary { call | member } ;
-call           = "(" [ expression { "," expression } ] ")" ;
-member         = "." name ;
-primary        = literal | declaration | name | "(" expression ")" ;
-declaration    = type-name name ;
-type-name      = builtin-type | name ;
-```
-
-`literal` включает строковый, числовой, булев и `null` литералы. Комментарии `// ...` и пробельные символы между токенами игнорируются.