Revert wrong sync in 5958c305e5 [ci skip]

sync_default_gems.rb sometimes syncs too much.

README.md

@@ -54,57 +54,6 @@ see [Building Ruby](doc/contributing/building_ruby.md)
 
 https://www.ruby-lang.org/
 
-## Commands
-
-The following commands are available on IRB.
-
-* `cwws`
-  * Show the current workspace.
-* `cb`, `cws`, `chws`
-  * Change the current workspace to an object.
-* `bindings`, `workspaces`
-  * Show workspaces.
-* `edit`
-  * Open a file with the editor command defined with `ENV["EDITOR"]`
-    * `edit` - opens the file the current context belongs to (if applicable)
-    * `edit foo.rb` - opens `foo.rb`
-    * `edit Foo` - opens the location of `Foo`
-    * `edit Foo.bar` - opens the location of `Foo.bar`
-    * `edit Foo#bar` - opens the location of `Foo#bar`
-* `pushb`, `pushws`
-  * Push an object to the workspace stack.
-* `popb`, `popws`
-  * Pop a workspace from the workspace stack.
-* `load`
-  * Load a Ruby file.
-* `require`
-  * Require a Ruby file.
-* `source`
-  * Loads a given file in the current session.
-* `irb`
-  * Start a child IRB.
-* `jobs`
-  * List of current sessions.
-* `fg`
-  * Switches to the session of the given number.
-* `kill`
-  * Kills the session with the given number.
-* `help`
-  * Enter the mode to look up RI documents.
-* `irb_info`
-  * Show information about IRB.
-* `ls`
-  * Show methods, constants, and variables.
-    `-g [query]` or `-G [query]` allows you to filter out the output.
-* `measure`
-  * `measure` enables the mode to measure processing time. `measure :off` disables it.
-* `$`, `show_source`
-  * Show the source code of a given method or constant.
-* `@`, `whereami`
-  * Show the source code around binding.irb again.
-* `debug`
-  * Start the debugger of debug.gem.
-
 ## Documentation
 
 - [English](https://docs.ruby-lang.org/en/master/index.html)