Module#delegate avoid creating a unique fstring for each delegator

For example:

```ruby
delegate :negative?, to: :value, as: Numeric
```

Before:

```
def negative?(&block)
  _ = @value
  _.negative?(&block)
rescue NoMethodError => e
  if _.nil? && e.name == :negative?
    raise DelegationError, "ActiveSupport::Duration#negative? delegated to @value.negative?, but @value is nil: #{self.inspect}"
  else
    raise
  end
end
```

After:

```ruby
def negative?(&block)
  _ = @value
  _.negative?(&block)
rescue NoMethodError => e
  if _.nil? && e.name == :negative?
    raise DelegationError.nil_target(:negative?, :"@value")
  else
    raise
  end
end
```

Before almost every delegator would generate a large unique string that gets interned for
the error message that is rarely if ever used.

Rather than to "hardcode" a unique string, we now only pass pre-existing symbols to
a method helper that will build the error message.

This alone saves about 160B per delegator, and the method bytecode is also marginally
smaller (but it's harder to assess how much this actually saves)

Author: byroot

activesupport/lib/active_support/core_ext/module/delegation.rb

@@ -5,7 +5,13 @@
 class Module
   # Error generated by +delegate+ when a method is called on +nil+ and +allow_nil+
   # option is not used.
-  class DelegationError < NoMethodError; end
+  class DelegationError < NoMethodError
+    class << self
+      def nil_target(method_name, target) # :nodoc:
+        new("#{method_name} delegated to #{target}, but #{target} is nil")
+      end
+    end
+  end
 
   RUBY_RESERVED_KEYWORDS = %w(__ENCODING__ __LINE__ __FILE__ alias and BEGIN begin break
   case class def defined? do else elsif END end ensure false for if in module next nil
@@ -266,7 +272,7 @@ def delegate(*methods, to: nil, prefix: nil, allow_nil: nil, private: nil, as: n
           "  _.#{method}(#{definition})" <<
           "rescue NoMethodError => e" <<
           "  if _.nil? && e.name == :#{method}" <<
-          %(   raise DelegationError, "#{self}##{method_name} delegated to #{receiver}.#{method}, but #{receiver} is nil: \#{self.inspect}") <<
+          "    raise DelegationError.nil_target(:#{method_name}, :'#{receiver}')" <<
           "  else" <<
           "    raise" <<
           "  end" <<
@@ -347,7 +353,7 @@ def method_missing(method, ...)
               if #{allow_nil == true}
                 nil
               else
-                raise DelegationError, "\#{method} delegated to #{target}, but #{target} is nil"
+                raise DelegationError.nil_target(method, :'#{target}')
               end
             else
               raise