small refactor

components/header.typ

@@ -0,0 +1,18 @@
+#import "../common.typ": *
+
+#let rev() = [
+  #if git_rev != "" {[
+    Git revision #flink("https://github.com/alex-s168/website/tree/" + git_rev)[\##short_git_rev]
+  ]}
+
+  #if git_commit_date != "" {[
+    Modified at #git_commit_date
+  ]}
+]
+
+// authors is list of people in common:people
+#let rev-and-authors(authors) = [
+  #rev()
+
+  Written by #authors.map((p) => person(p)).join[, ]
+]