Docs: Copy "CodeQL for Go" docs into this repo

docs/language/learn-ql/go/ast.dot

@@ -0,0 +1,22 @@
+digraph ast {
+    graph [dpi=300];
+    "x" [shape=rect];
+    "y" [shape=rect];
+    "x + y" [shape=rect];
+    "(x + y)" [shape=rect];
+    "z" [shape=rect];
+    "(x + y) * z" [shape=rect];
+    invis1 [style=invis];
+    invis2 [style=invis];
+    invis3 [style=invis];
+
+    "(x + y) * z" -> "(x + y)" [label=" 0"];
+    "(x + y) * z" -> "z" [label=" 1"];
+    "(x + y)" -> "x + y" [label=" 0"];
+    "x + y" -> "x" [label=" 0"];
+    "x + y" -> "y" [label=" 1"];
+
+    "z" -> invis1 [style=invis];
+    invis1 -> invis2 [style=invis];
+    invis1 -> invis3 [style=invis];
+}

docs/language/learn-ql/go/cfg.dot

@@ -0,0 +1,8 @@
+digraph cfg {
+    graph [dpi=300];
+    rankdir=LR;
+    "x := 0" -> "p != nil";
+    "p != nil" -> "x = p.f";
+    "p != nil" -> "return x";
+    "x = p.f" -> "return x";
+}

docs/language/learn-ql/go/cfg2.dot

@@ -0,0 +1,14 @@
+digraph cfg2 {
+    graph [dpi=300];
+    rankdir=LR;
+
+    "p != nil is true" [shape=box];
+    "p != nil is false" [shape=box];
+
+    "x := 0" -> "p != nil";
+    "p != nil" -> "p != nil is true";
+    "p != nil is true" -> "x = p.f";
+    "p != nil" -> "p != nil is false";
+    "p != nil is false" -> "return x";
+    "x = p.f" -> "return x";
+}

docs/language/learn-ql/go/dfg.dot

@@ -0,0 +1,11 @@
+digraph dfg {
+    graph [dpi=300];
+    rankdir=LR;
+
+    "x" [shape=diamond];
+    "return x" [label=<return <u>x</u>>];
+
+    "0" -> "x";
+    "p.f" -> "x";
+    "x" -> "return x";
+}

docs/language/learn-ql/go/ql-for-go.rst

@@ -3,9 +3,16 @@ CodeQL for Go
 
 Experiment and learn how to write effective and efficient queries for CodeQL databases generated from Go codebases.
 
+.. toctree::
+   :hidden:
+
+   introduce-libraries-go
+
 -  `Basic Go query <https://lgtm.com/help/lgtm/console/ql-go-basic-example>`__: Learn to write and run a simple CodeQL query using LGTM.
 
-Other resources
+-  :doc:`CodeQL library for Go <introduce-libraries-go>`: When you're analyzing a Go program, you can make use of the large collection of classes in the CodeQL library for Go.
+
+Further reading
 ---------------
 
 -  For the queries used in LGTM, display a `Go query <https://lgtm.com/search?q=language%3Ago&t=rules>`__ and click **Open in query console** to see the code used to find alerts.

docs/language/learn-ql/go/ssa.dot

@@ -0,0 +1,15 @@
+digraph ssa {
+    graph [dpi=300];
+    rankdir=LR;
+
+    "x1" [shape=diamond,label=<x<sub>1</sub>>];
+    "x2" [shape=diamond,label=<x<sub>2</sub>>];
+    "x3" [shape=diamond,label=<x<sub>3</sub>>];
+    "return x" [label=<return <u>x</u>>];
+
+    "0" -> "x1";
+    "p.f" -> "x2";
+    "x1" -> "x3";
+    "x2" -> "x3";
+    "x3" -> "return x";
+}