feat(smartlog): switch from ◯ to ○ for visible commit nodes

U+25EF is unicode LARGE CIRCLE thus would be rendered visibly larger than other node.
I believe U+25CB WHITE CIRCLE should be used instead.

Author: xuanduc987

git-branchless-lib/src/core/formatting.rs

@@ -198,7 +198,7 @@ impl Glyphs {
             vertical_ellipsis: "⋮",
             split: "━┓",
             merge: "━┛",
-            commit_visible: "◯",
+            commit_visible: "○",
             commit_visible_head: "●",
             commit_obsolete: "✕",
             commit_obsolete_head: "⦻",