Add GMarkdown (#1863)

Author: GIKICoder

contents.json

@@ -5502,6 +5502,12 @@
       "description":"Easy to use, very customisable pin entry.",
       "homepage":"https://github.com/Fawxy/CBPinEntryView"
     },
+    {
+      "title":"GMarkdown",
+      "category":"text",
+      "description":"Markdown rendering library for iOS with support for tables, LaTeX, Mermaid, and code highlighting.",
+      "homepage":"https://github.com/GIKICoder/GMarkdown"
+    },
     {
       "title":"MarkdownView",
       "category":"text",