feat(icons): Add mail-pen icon (#4399)

* Add mail pen icon

* Update icons/mail-pen.svg

Co-authored-by: Karsa <contact@karsa.org>

* Update mail-pen.svg

* Update mail-pen.json

Added contributors from mail & missing metadata

---------

Co-authored-by: Eric Fennis <eric.fennis@gmail.com>
Co-authored-by: Karsa <contact@karsa.org>

icons/mail-pen.json

@@ -0,0 +1,31 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "colebemis",
+    "karsa-mistmere",
+    "ericfennis",
+    "jguddas",
+    "jennieboops"
+  ],
+  "use-cases": [
+    "Composing or editing email messages",
+    "Drafting letters in mail interfaces",
+    "Editing email addresses on settings pages"
+  ],
+  "tags": [
+    "email",
+    "message",
+    "letter",
+    "pen",
+    "edit",
+    "compose",
+    "draft",
+    "write",
+    "writing",
+    "create",
+    "reply"
+  ],
+  "categories": [
+    "mail"
+  ]
+}

icons/mail-pen.svg

@@ -0,0 +1,15 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M15.506 17.646A2 2 0 0015 18.5l-.837 2.87a.5.5 0 00.62.62l2.87-.837a2 2 0 00.854-.506l3.013-3.009a1 1 0 00-3.004-3.004z" />
+  <path d="M22 10.346V6a2 2 0 00-2-2H4a2 2 0 00-2 2v12a2 2 0 002 2h6.396" />
+  <path d="m22 7-8.991 5.727a2 2 0 01-2.009 0L2 7" />
+</svg>