ZJIT: Avoid documenting internal methods

A different doc-test fix from 238aaa4cda14add04f7ecb4ff6fc52719589e89d.
They're not supposed to be public in the first place.

zjit.rb

@@ -61,7 +61,14 @@ class << RubyVM::ZJIT
     buf
   end
 
-  # Outputs counters into +buf+.
+  # Assert that any future ZJIT compilation will return a function pointer
+  def assert_compiles # :nodoc:
+    Primitive.rb_zjit_assert_compiles
+  end
+
+  # :stopdoc:
+  private
+
   def print_counters(keys, buf:, stats:)
     left_pad = keys.map(&:size).max + 1
     keys.each do |key|
@@ -83,7 +90,6 @@ class << RubyVM::ZJIT
     end
   end
 
-  # Similar to #print_counters but only includes keys that start with +prefix+.
   def print_counters_with_prefix(buf:, stats:, prefix:, prompt:)
     keys = stats.keys.select { |key| key.start_with?(prefix) && stats[key] > 0 }
     unless keys.empty?
@@ -92,14 +98,6 @@ class << RubyVM::ZJIT
     end
   end
 
-  # Assert that any future ZJIT compilation will return a function pointer
-  def assert_compiles # :nodoc:
-    Primitive.rb_zjit_assert_compiles
-  end
-
-  # :stopdoc:
-  private
-
   def number_with_delimiter(number)
     s = number.to_s
     i = s.index('.') || s.size