chore(docs): update file HCL function (#18696)

website/content/docs/job-specification/hcl2/functions/file/file.mdx

@@ -9,7 +9,7 @@ description: |-
 # `file` Function
 
 `file` reads the contents of a file at the given path and returns them as
-a string.
+a string. Relative paths will be resolved based on the CLI’s current working directory.
 
 ```hcl
 file(path)
@@ -30,6 +30,31 @@ so this function can only be used with files that are already present on disk on
 Hello World
 ```
 
+Or in an example job specification:
+
+```hcl
+# /path/to/example/jobspec.nomad
+job "test" {
+  group "test" {
+    task "test" {
+      driver = "docker"
+      config {
+        image  = "test/image:latest"
+
+        volumes = [
+          "local/file.txt:/path/to/file/on/container/file.txt"
+        ]
+      }
+
+      template {
+        data        = file("/path/to/example/file.txt")
+        destination = "local/file.txt"
+      }
+    }
+  }
+}
+```
+
 ## Related Functions
 
 - [`fileexists`](/nomad/docs/job-specification/hcl2/functions/file/fileexists) determines whether a file exists