feat: support operator== for Literal/Manifest/ManifestList

[dongxiao1198]

add operator== for manifest and manifest list

[mapleFU]

Can we use

class T {
public:
  bool operator==(const T&) const = default;

? ( Literal can also add bool operator== default )

[dongxiao1198]

Can we use

class T {
public:
  bool operator==(const T&) const = default;

? ( Literal can also add bool operator== default )

Can we use

class T {
public:
  bool operator==(const T&) const = default;

? ( Literal can also add bool operator== default )

Of course yes，but there is already have operator<=>， so..

[mapleFU]

I mean:

class Literal {
public:
+  bool operator==(const Literal& lit) const {
+     ...
+  }
};

and

class Manifest {
 // using auto generated
};

[dongxiao1198]

I mean:

class Literal {
public:
+  bool operator==(const Literal& lit) const {
+     ...
+  }
};

and

class Manifest {
 // using auto generated
};

ok。。 that will be much more simple

[Xuanwo]

Thank you @dongxiao1198 for working on this