add docs for sensitive variables

website/pages/docs/from-1.5/blocks/variable.mdx

@@ -30,6 +30,8 @@ Example of a variable assignment from a file:
 
 `@include 'from-1.5/variables/must-be-set.mdx'`
 
+`@include 'from-1.5/variables/sensitive.mdx'`
+
 # More on variables
 
 - Read the [full variables](/docs/from-1.5/variables) description for a more

website/pages/docs/from-1.5/variables.mdx

@@ -356,3 +356,5 @@ other variables: the last value found overrides the previous values.
 |   `var.bar` in .pkr.hcl file   | error, "bar undeclared" |  error, "bar undeclared"  |
 |     `-var bar=yz` argument     | error, "bar undeclared" |  error, "bar undeclared"  |
 |    `export PKR_VAR_bar=yz`     |            -            |             -             |
+
+`@include 'from-1.5/variables/sensitive.mdx'`

website/pages/partials/from-1.5/variables/foo-block.mdx

@@ -1,8 +1,11 @@
 ```hcl
 # variables.pkr.hcl
 variable "foo" {
-    type = string
-    default = "the default value of the `foo` variable"
+    type        = string
+    default     = "the default value of the `foo` variable"
     description = "description of the `foo` variable"
+    sensitive   = false
+    # When a variable is sensitive all string-values from that variable will be
+    # obfuscated from Packer's output.
 }
 ```

website/pages/partials/from-1.5/variables/sensitive.mdx

@@ -0,0 +1,23 @@
+## A variable can be sensitive
+
+When a variable is sensitive all string-values from that variable will be
+obfuscated from Packer's output :
+
+```hcl
+# var-foo.pkr.hcl
+variable "foo" {
+    sensitive = true
+    default   = {
+        key = "SECR3TP4SSW0RD"
+    }
+}
+```
+
+```shell-session
+$ packer inspect var-foo.pkr.hcl
+Packer Inspect: HCL2 mode
+
+> input-variables:
+var.foo: "{\n  \"key\" = \"<sensitive>\"\n }"
+...
+```