Adds generic merge and split icons (#1167)

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

icons/merge.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "combine",
+    "join",
+    "unite"
+  ],
+  "categories": [
+    "development",
+    "arrows"
+  ]
+}

icons/merge.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="m8 6 4-4 4 4" />
+  <path d="M12 2v10.3a4 4 0 0 1-1.172 2.872L4 22" />
+  <path d="m20 22-5-5" />
+</svg>

icons/split.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "break",
+    "disband",
+    "divide",
+    "separate",
+    "branch",
+    "disunite"
+  ],
+  "categories": [
+    "development",
+    "arrows"
+  ]
+}

icons/split.svg

@@ -0,0 +1,16 @@
+<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="M16 3h5v5" />
+  <path d="M8 3H3v5" />
+  <path d="M12 22v-8.3a4 4 0 0 0-1.172-2.872L3 3" />
+  <path d="m15 9 6-6" />
+</svg>