Extract mutex_m as bundled gems

doc/maintainers.md

@@ -181,11 +181,6 @@ have commit right, others don't.
 * https://github.com/ruby/logger
 * https://rubygems.org/gems/logger
 
-#### lib/mutex_m.rb
-* Keiju ISHITSUKA (keiju)
-* https://github.com/ruby/mutex_m
-* https://rubygems.org/gems/mutex_m
-
 #### lib/net/http.rb, lib/net/https.rb
 * NARUSE, Yui (naruse)
 * https://github.com/ruby/net-http
@@ -487,6 +482,9 @@ have commit right, others don't.
 ### racc
 * https://github.com/ruby/racc
 
+#### mutex_m
+* https://github.com/ruby/mutex_m
+
 
 ## Platform Maintainers
 ### mswin64 (Microsoft Windows)

doc/standard_library.rdoc

@@ -53,7 +53,6 @@ IPAddr:: Provides methods to manipulate IPv4 and IPv6 IP addresses
 IRB:: Interactive Ruby command-line tool for REPL (Read Eval Print Loop)
 OptionParser:: Ruby-oriented class for command-line option analysis
 Logger:: Provides a simple logging utility for outputting messages
-Mutex_m:: Mixin to extend objects to be handled like a Mutex
 Net::HTTP:: HTTP client api for Ruby
 Observable:: Provides a mechanism for publish/subscribe pattern in Ruby
 Open3:: Provides access to stdin, stdout and stderr when running other programs
@@ -130,3 +129,4 @@ RBS:: RBS is a language to describe the structure of Ruby programs
 TypeProf:: A type analysis tool for Ruby code based on abstract interpretation
 DEBUGGER__:: Debugging functionality for Ruby
 Racc:: A LALR(1) parser generator written in Ruby.
+Mutex_m:: Mixin to extend objects to be handled like a Mutex

gems/bundled_gems

@@ -21,3 +21,4 @@ rbs             3.4.1   https://github.com/ruby/rbs
 typeprof        0.21.9  https://github.com/ruby/typeprof
 debug           1.9.1   https://github.com/ruby/debug
 racc            1.7.3   https://github.com/ruby/racc
+mutex_m         0.2.0   https://github.com/ruby/mutex_m