feat(templater): add absPath template function (#2788)

Signed-off-by: Mateen Anjum <mateenali66@gmail.com>
Co-authored-by: Valentin Maerten <maerten.valentin@gmail.com>

website/src/docs/reference/templating.md

@@ -617,6 +617,7 @@ tasks:
       - echo "{{.WIN_PATH | fromSlash}}"                        # Convert to OS-specific slashes
       - echo "{{joinPath .OUTPUT_DIR .BINARY_NAME}}"            # Join path elements
       - echo "Relative {{relPath .ROOT_DIR .TASKFILE_DIR}}"    # Get relative path
+      - echo '{{absPath "../sibling"}}'                         # Resolve to an absolute path
 ```
 
 ### Data Structure Functions