RJIT: Clean up unnecessary documentation

doc/.document

@@ -7,4 +7,5 @@ syntax
 optparse
 rdoc
 regexp
+rjit
 yjit

doc/rjit/rjit.md

@@ -24,13 +24,6 @@ You may still manually pass `--enable-rjit` to try RJIT on unsupported platforms
 
 It enables `--rjit-dump-disasm` if libcapstone is available.
 
-It also enables `vm_insns_count` and `ratio_in_rjit` in `--rjit-stats`.
-However, it makes the interpreter a little slower.
-
-### --enable-rjit=disasm
-
-It enables `--rjit-dump-disasm` if libcapstone is available.
-
 ## make
 ### rjit-bindgen
 
@@ -42,12 +35,11 @@ macOS seems to have libclang by default. On Ubuntu, you can install it with `apt
 ## ruby
 ### --rjit-stats
 
-This prints RJIT stats at exit. Some stats are available only with `--enable-rjit=dev` on configure.
+This prints RJIT stats at exit.
 
 ### --rjit-dump-disasm
 
-This dumps all JIT code. You need to install libcapstone before configure and use `--enable-rjit=dev`
-or `--enable-rjit=disasm` on configure.
+This dumps all JIT code. You need to install libcapstone before configure and use `--enable-rjit=dev` on configure.
 
 * Ubuntu: `sudo apt-get install -y libcapstone-dev`
 * macOS: `brew install capstone`

lib/ruby_vm/rjit/.document

@@ -0,0 +1 @@
+stats.rb

lib/ruby_vm/rjit/stats.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 module RubyVM::RJIT
+  # Return a Hash for \RJIT statistics. \--rjit-stats makes more information available.
   def self.runtime_stats
     stats = {}
 
@@ -30,6 +31,7 @@ module RubyVM::RJIT
     stats
   end
 
+  # :nodoc: all
   class << self
     private
 

rjit.rb

@@ -1,10 +1,10 @@
 module RubyVM::RJIT
-  # Return true if RJIT is enabled.
+  # Return true if \RJIT is enabled.
   def self.enabled?
     Primitive.cexpr! 'RBOOL(rb_rjit_enabled)'
   end
 
-  # Start generating JITed code again after --rjit-disable.
+  # Start JIT compilation after \--rjit-disable.
   def self.enable
     Primitive.cstmt! %{
       rb_rjit_call_p = true;