Remove KEYWORD_ALIASES which handled special alias name of irb_break irb_catch and irb_next command

lib/irb/command/help.rb

@@ -39,7 +39,7 @@ def help_message
 
         help_cmds = commands_grouped_by_categories.delete("Help")
         no_category_cmds = commands_grouped_by_categories.delete("No category")
-        aliases = irb_context.instance_variable_get(:@user_aliases).map do |alias_name, target|
+        aliases = irb_context.instance_variable_get(:@command_aliases).map do |alias_name, target|
           { display_name: alias_name, description: "Alias for `#{target}`" }
         end
 

lib/irb/context.rb

@@ -150,25 +150,14 @@ def initialize(irb, workspace = nil, input_method = nil)
       end
 
       @user_aliases = IRB.conf[:COMMAND_ALIASES].dup
-      @command_aliases = @user_aliases.merge(KEYWORD_ALIASES)
+      @command_aliases = @user_aliases.dup
     end
 
     private def term_interactive?
       return true if ENV['TEST_IRB_FORCE_INTERACTIVE']
       STDIN.tty? && ENV['TERM'] != 'dumb'
     end
 
-    # because all input will eventually be evaluated as Ruby code,
-    # command names that conflict with Ruby keywords need special workaround
-    # we can remove them once we implemented a better command system for IRB
-    KEYWORD_ALIASES = {
-      :break => :irb_break,
-      :catch => :irb_catch,
-      :next => :irb_next,
-    }.freeze
-
-    private_constant :KEYWORD_ALIASES
-
     def use_tracer=(val)
       require_relative "ext/tracer" if val
       IRB.conf[:USE_TRACER] = val

lib/irb/default_commands.rb

@@ -181,9 +181,15 @@ def load_command(command)
       [:edit, NO_OVERRIDE]
     )
 
-    _register_with_aliases(:irb_break, Command::Break)
-    _register_with_aliases(:irb_catch, Command::Catch)
-    _register_with_aliases(:irb_next, Command::Next)
+    _register_with_aliases(:irb_break, Command::Break,
+      [:break, OVERRIDE_ALL]
+    )
+    _register_with_aliases(:irb_catch, Command::Catch,
+      [:catch, OVERRIDE_PRIVATE_ONLY]
+    )
+    _register_with_aliases(:irb_next, Command::Next,
+      [:next, OVERRIDE_ALL]
+    )
     _register_with_aliases(:irb_delete, Command::Delete,
       [:delete, NO_OVERRIDE]
     )