fix: remove unnecessary derive for git_merge_file_input and update from_raw implementation

Author: chalharu

libgit2-sys/lib.rs

@@ -1561,7 +1561,6 @@ pub struct git_merge_file_options {
 }
 
 #[repr(C)]
-#[derive(Copy, Clone)]
 pub struct git_merge_file_input {
     pub version: c_uint,
     pub ptr: *const c_char,

src/merge.rs

@@ -428,12 +428,8 @@ impl Default for MergeFileInput<'_> {
 impl Binding for MergeFileInput<'_> {
     type Raw = *const raw::git_merge_file_input;
 
-    unsafe fn from_raw(raw: *const raw::git_merge_file_input) -> MergeFileInput<'static> {
-        MergeFileInput {
-            raw: *raw,
-            path: None,
-            content: None,
-        }
+    unsafe fn from_raw(_raw: *const raw::git_merge_file_input) -> MergeFileInput<'static> {
+        panic!("unimplemened")
     }
 
     fn raw(&self) -> *const raw::git_merge_file_input {