Add square-* code snippet/gist icons (#1068)

* Add `square-dashed-bottom` (snippet) icon

* Add `square-code` (gist) icon

* Optimise `square-dashed-bottom` (snippet) icon

* Optimise `square-code` (gist) icon

* Add `square-dashed-bottom-code` (snippet/gist) icon

* Update icons/square-dashed-bottom.svg

Co-authored-by: Jakob Guddas <github@jguddas.de>

* Refine `square-dashed-bottom-code` icon

---------

Co-authored-by: Jakob Guddas <github@jguddas.de>

icons/square-code.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "gist",
+    "source",
+    "programming",
+    "html",
+    "xml",
+    "coding"
+  ],
+  "categories": [
+    "text",
+    "development"
+  ]
+}

icons/square-code.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"
+>
+  <rect width="18" height="18" x="3" y="3" rx="2" />
+  <path d="m10 10-2 2 2 2" />
+  <path d="m14 14 2-2-2-2" />
+</svg>

icons/square-dashed-bottom-code.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "rectangle",
+    "aspect ratio",
+    "1:1",
+    "shape",
+    "snippet",
+    "code",
+    "coding"
+  ],
+  "categories": [
+    "shapes",
+    "development",
+    "files"
+  ]
+}

icons/square-dashed-bottom-code.svg

@@ -0,0 +1,17 @@
+<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="m10 10-2 2 2 2" />
+  <path d="m14 14 2-2-2-2" />
+  <path d="M5 21a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2" />
+  <path d="M9 21h1" />
+  <path d="M14 21h1" />
+</svg>

icons/square-dashed-bottom.json

@@ -0,0 +1,17 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "rectangle",
+    "aspect ratio",
+    "1:1",
+    "shape",
+    "snippet",
+    "code",
+    "coding"
+  ],
+  "categories": [
+    "shapes",
+    "development",
+    "files"
+  ]
+}

icons/square-dashed-bottom.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="M5 21a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2" />
+  <path d="M9 21h1" />
+  <path d="M14 21h1" />
+</svg>