Local variable assignment being incorrectly recognised as debugging commands

[st0012]

Description

When assigning a local variable which's name is the same one of the debugging commands (e.g. info), it'd be treated as the command call instead of a local assignment:

irb(main):001> info = 123
`debug` command is only available when IRB is started with binding.irb
=> nil

[tompng]

We can check command-like assignment by regexp like /\A#{COMMAND_NAME} (=|\+=|-=|\*=|...)/

info = 123
info += 1
info <<= 1

Now, using local variable info seems hard because the code below will be treated as command

info + 1
info << 1
info > 42

But maybe this can be solved by extending the command-method override policy (NO_OVERRIDE OVERRIDE_ALL OVERRIDE_PRIVATE_ONLY) to also check local variables existence.

[tompng]

Fixed by #961

irb(main):001> info
Debugging commands are only available when IRB is started with binding.irb
irb(main):002> info = 123
=> 123
irb(main):003> info
=> 123

The problem is not solved in irb:rdbg mode but it's an issue of ruby/debug ruby/debug#1108

irb:rdbg(main):003> info = 123
unrecognized argument for info command: = 123