change BFGS name and make lattice_change_cg and ions_move_cg shorter

[19hello]

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[QuantumMisaka]

@19hello Hi! You need to tell us what are you specifically doing in your PR. and all your change in the name of INPUT variable must also be changed in docs.

[19hello]

@19hello Hi! You need to tell us what are you specifically doing in your PR. and all your change in the name of INPUT variable must also be changed in docs.

I have changed the data type of the relax_method parameter from string to vector. With this modification, the relax_method parameter can now include a number after the optimization algorithm name to control whether to use the new or old BFGS algorithm. If no number is specified, the new BFGS algorithm will be used by default. This change does not affect the usage of other algorithms like CG ,users can still simply input the algorithm name as before.