fix: preserve selection direction when searching for char pair

`find_nth_closests_pairs_pos` checks the direction backward or forward. This helps preserve the selection direction when pressing `mim` or `mam`. This commit also adds this functionality to `find_nth_pairs_pos`, so `mi(` or `ma}` also preserves direction now.

helix-core/src/surround.rs

@@ -160,7 +160,10 @@ pub fn find_nth_pairs_pos(
         )
     };
 
-    Option::zip(open, close).ok_or(Error::PairNotFound)
+    match range.direction() {
+        Direction::Forward => Option::zip(open, close).ok_or(Error::PairNotFound),
+        Direction::Backward => Option::zip(close, open).ok_or(Error::PairNotFound),
+    }
 }
 
 fn find_nth_open_pair(

helix-term/tests/test/movement.rs

@@ -106,6 +106,26 @@ async fn surround_by_character() -> anyhow::Result<()> {
     ))
     .await?;
 
+    // Selection direction is preserved
+    test((
+        "(so [many {go#[|od]#} text] here)",
+        "mi{",
+        "(so [many {#[|good]#} text] here)",
+    ))
+    .await?;
+    test((
+        "(so [many {go#[|od]#} text] here)",
+        "mi[",
+        "(so [#[|many {good} text]#] here)",
+    ))
+    .await?;
+    test((
+        "(so [many {go#[od|]#} text] here)",
+        "mi(",
+        "(#[so [many {good} text] here|]#)",
+    ))
+    .await?;
+
     Ok(())
 }