Demangle flags symbols

[ret2libc]

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• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• I've added tests that prove my fix is effective or that my feature works (if possible)
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Detailed description

I'd like to have asm.flags.real=true by default, however one of the problems with having that enabled is that the users cannot easily know what is the flag name they should use to reference the symbol.

For example:

call  std::vector<int, std::allocator<int> >::vector()

It is not immediately clear that the flag name (which should be used in commands like s) is method.std::vector_int__std::allocator_int___.vector.

The idea is that we want the flag name to be displayed as comment (but only when the real names are displayed!):

-> asm.flags.real=true

call  std::vector<int, std::allocator<int> >::vector() ; method.std::vector_int__std::allocator_int___.vector

-> asm.flags.real=false
call  method.std::vector_int__std::allocator_int___.vector

These comments are not displayed in visual mode because the user can easily use the "jumpkeys"(the numbers near the calls e.g. [1]) to move between functions.

Test plan

See attached test.
Moreover, ensure that in visual mode the comments are not displayed.

Closing issues

...

[XVilka]

See also these related bugs: #3656 and #3543

[ret2libc]

@XVilka about the test, please see 98f9449 . Also, i shared some concern in mattermost, but i don't know anything about RISCV.