git-commit-graph: add page (#5109)

pages/common/git-commit-graph.md

@@ -0,0 +1,16 @@
+# git commit-graph
+
+> Write and verify Git commit-graph files.
+> More information: <https://git-scm.com/docs/git-commit-graph>.
+
+- Write a commit-graph file for the packed commits in the repository's local `.git` directory:
+
+`git commit-graph write`
+
+- Write a commit-graph file containing all reachable commits:
+
+`git show-ref --hash | git commit-graph write --stdin-commits`
+
+- Write a commit-graph file containing all commits in the current commit-graph file along with those reachable from `HEAD`:
+
+`git rev-parse {{HEAD}} | git commit-graph write --stdin-commits --append`