Update documentation for HCL analysis capabilities

Author: GeekMasher

ql/lib/hcl.qll

@@ -1,3 +1,17 @@
+/**
+ * Comprehensive analysis capabilities for HCL (HashiCorp Configuration Language) files.
+ * This library includes AST analysis, resource definitions, security checks, provider-specific
+ * functionality, and support for Terraform configurations.
+ *
+ * The library offers the following main components:
+ * - AST nodes and expressions for analyzing HCL syntax and structure
+ * - Resource and data source analysis for infrastructure components
+ * - Variable, local, and constant value tracking
+ * - Provider-specific classes for AWS, Azure, GCP, and other cloud providers
+ * - Security analysis for detecting hardcoded secrets and misconfigurations
+ * - Terraform-specific functionality for modules, state, and workflows
+ */
+
 import codeql.Locations
 import codeql.files.FileSystem
 import codeql.hcl.ast.AstNodes