Clarify comments in code.

flax/linen/linear.py

@@ -695,14 +695,16 @@ def __call__(self, inputs: Array) -> Array:
           -(y_dim - x_dim) % (2 * x_dim)
           for y_dim, x_dim in zip(y.shape[1:-1], scaled_x_dims)
       ]
-      # Divide the padding equally between left and right. The choice to put
-      # "+1" on the left (and not on the right) represents a convention for
-      # aligning even-sized kernels.
+      # Divide the padding equally between left and right.
       if self.transpose_kernel:
+        # The choice to put "+1" on the right (and not on the left)
+        # represents a convention for aligning kernels.
         total_pad = [
             (size_diff // 2, (size_diff + 1) // 2) for size_diff in size_diffs
         ]
       else:
+        # This was the convention chosen previously and is kept here for
+        # backward compatibility.
         total_pad = [
             ((size_diff + 1) // 2, size_diff // 2) for size_diff in size_diffs
         ]