[Enhancement] The output code style of override API can be more compact

[Peefy]

Enhancement

In the current KCL version, for the following code (main.k)

schema Config:
    a: {str:}

c = Config {
    a = {b = 1}
}

Run the following code:

kcl main.k -O c.a.c=2 -d

We can get the code as follows:

schema Config:
    a: {str:}

c = Config {
    a = {b = 1}
    a.c = 2
}

This issue aims to improve the compactness of KCL override code by modifying the code as much as possible according to the override path. For example, for the above code, after being overridden, the following code is output

schema Config:
    a: {str:}

c = Config {
    a = {
        b = 1
        c = 2 # Avoid outputting common config paths `a` for `a.b` and `a.c`
    }
}