feat!: replace tree::Options::allow_lossy_resolution with *::tree_conflicts.

That way it's possible to steer how to resolve tree-related conflicts while
making it possible to detect that a conflict happened.

Author: Byron

Diff for: gix-merge/tests/fixtures/generated-archives/tree-baseline.tar

@@ -222,6 +222,26 @@ git init rename-add-symlink
   git commit -m "rename foo to bar"
 )
 
+git init rename-add-same-symlink
+(cd rename-add-same-symlink
+  touch target
+  ln -s target link
+  git add .
+  git commit -m "original"
+
+  git branch A
+  git branch B
+
+  git checkout A
+  git mv link link-new
+  git commit -m "rename link to link-new"
+
+  git checkout B
+  ln -s target link-new
+  git add link-new
+  git commit -m "create link-new"
+)
+
 git init rename-rename-plus-content
 (cd rename-rename-plus-content
   write_lines 1 2 3 4 5 >foo
@@ -993,7 +1013,7 @@ git init type-change-to-symlink
 
 
 
-# TODO: Git does not detect the conflict (one turns exe off, the other turns it on), and we do exactly the same.
+baseline rename-add-same-symlink A-B A B
 baseline rename-add-exe-bit-conflict A-B A B
 baseline remove-executable-mode A-B A B
 baseline simple side-1-3-without-conflict side1 side3

Diff for: gix-merge/tests/fixtures/tree-baseline.sh

@@ -130,27 +130,15 @@ fn run_baseline() -> crate::Result {
             actual.conflicts,
             merge_info.conflicts
         );
-        // if case_name.starts_with("submodule-both-modify-A-B") {
-        if false {
-            assert!(
-                !did_change,
-                "{case_name}: We can't handle submodules, so there is no index change"
-            );
-            assert!(
-                actual.has_unresolved_conflicts(conflicts_like_in_git),
-                "{case_name}: submodules currently result in an unresolved (unknown) conflict"
-            );
-        } else {
-            assert_eq!(
-                did_change,
-                actual.has_unresolved_conflicts(conflicts_like_in_git),
-                "{case_name}: If there is any kind of conflict, the index should have been changed"
-            );
-        }
+        assert_eq!(
+            did_change,
+            actual.has_unresolved_conflicts(conflicts_like_in_git),
+            "{case_name}: If there is any kind of conflict, the index should have been changed"
+        );
     }
 
     assert_eq!(
-        actual_cases, 107,
+        actual_cases, 109,
         "BUG: update this number, and don't forget to remove a filter in the end"
     );