Tweak config redirection code based on PR review.

Remove comments listing unsupported libgit2_opts signatures -- these are subject
to change. Instead just note that there are more signatures that could be
implemented in the future.

Fix some comments and names to be more accurate.

Fold the libgit2_opts declarations in a code region to keep things tidy.

Author: Ryan Roden-Corrent

LibGit2Sharp/Core/NativeMethods.cs

@@ -581,31 +581,24 @@ internal static extern int git_filter_unregister(
         [DllImport(libgit2)]
         internal static extern int git_libgit2_features();
 
+        #region git_libgit2_opts
+
         // Bindings for git_libgit2_opts(int option, ...):
         // Varargs can be bound using __arglist in .NET, but I had trouble getting that working with Mono.
-        // Instead of using __arglist, I enumerate the possible signatures here:
+        // Instead of using __arglist, I enumerate the possible signatures here.
+        // Currently only GIT_OPT_GET_SEARCH_PATH and GIT_OPT_SET_SEARCH_PATH are supported,
+        // but other overloads could be added using a similar pattern.
 
         // git_libgit2_opts(GIT_OPT_GET_SEARCH_PATH, int level, git_buf *buf)
         [DllImport(libgit2, CallingConvention = CallingConvention.Cdecl)]
         internal static extern int git_libgit2_opts(int option, uint level, GitBuf buf);
 
-        // git_libgit2_opts(GIT_OPT_GET_SEARCH_PATH, int level, git_buf *buf)
+        // git_libgit2_opts(GIT_OPT_SET_SEARCH_PATH, int level, const char *path)
         [DllImport(libgit2, CallingConvention = CallingConvention.Cdecl)]
         internal static extern int git_libgit2_opts(int option, uint level,
-            [MarshalAs(UnmanagedType.CustomMarshaler, MarshalCookie = UniqueId.UniqueIdentifier, MarshalTypeRef = typeof(StrictUtf8Marshaler))]string name);
+            [MarshalAs(UnmanagedType.CustomMarshaler, MarshalCookie = UniqueId.UniqueIdentifier, MarshalTypeRef = typeof(StrictUtf8Marshaler))]string path);
 
-        // Not yet implemented libgit2_opts signatures:
-        // git_libgit2_opts(GIT_OPT_GET_MWINDOW_SIZE, size_t*)
-        // git_libgit2_opts(GIT_OPT_SET_MWINDOW_SIZE, size_t)
-        // git_libgit2_opts(GIT_OPT_GET_MWINDOW_MAPPED_LIMIT, size_t*)
-        // git_libgit2_opts(GIT_OPT_SET_MWINDOW_MAPPED_LIMIT, size_t)
-        // git_libgit2_opts(GIT_OPT_SET_CACHE_OBJECT_LIMIT, git_otype type, size_t size)
-        // git_libgit2_opts(GIT_OPT_SET_CACHE_MAX_SIZE, ssize_t max_storage_bytes)
-        // git_libgit2_opts(GIT_OPT_ENABLE_CACHING, int enabled)
-        // git_libgit2_opts(GIT_OPT_GET_CACHED_MEMORY, ssize_t* current, ssize_t* allowed)
-        // git_libgit2_opts(GIT_OPT_GET_TEMPLATE_PATH, git_buf*out)
-        // git_libgit2_opts(GIT_OPT_SET_TEMPLATE_PATH, const char* path)
-        // git_libgit2_opts(GIT_OPT_SET_SSL_CERT_LOCATIONS, const char* file, const char* path)
+        #endregion
 
         [DllImport(libgit2)]
         internal static extern int git_graph_ahead_behind(out UIntPtr ahead, out UIntPtr behind, RepositorySafeHandle repo, ref GitOid one, ref GitOid two);