add doc

README.md

@@ -355,7 +355,7 @@ These examples incubate dotSCAD and dotSCAD refactors these examples. See [examp
 
  Signature | Description
 --|--
-**maxtrix/m_transpose**(m) | transpose a matrix.
+[**maxtrix/m_transpose**(m)](https://openhome.cc/eGossip/OpenSCAD/lib3x-m_transpose.html) | transpose a matrix.
 
 ## Surface
 

docs/lib3x-m_transpose.md

@@ -0,0 +1,30 @@
+# m_transpose
+
+It transposes a matrix.
+
+**Since:** 2.4
+
+## Parameters
+
+- `m` : A matrix.
+
+## Examples
+
+    use <matrix/m_transpose.scad>;
+
+    original_m = [
+        [1, 2, 3, 4],
+        [5, 6, 7, 8],
+        [9, 10, 11, 12]
+    ];
+
+    traget = [
+        [1, 5, 9],
+        [2, 6, 10],
+        [3, 7, 11],
+        [4, 8, 12]
+    ];
+
+    transposed = m_transpose(original_m);
+
+    assert(transposed == traget);

src/matrix/m_transpose.scad

@@ -1,3 +1,13 @@
+/**
+* m_transpose.scad
+*
+* @copyright Justin Lin, 2021
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib3x-m_transpose.html
+*
+**/
+
 function m_transpose(m) =
     let(
         column = len(m[0]),