xz: add lzma format examples (#2908)

pages/common/xz.md

@@ -1,15 +1,24 @@
 # xz
 
 > Compress or decompress .xz and .lzma files.
+> Homepage: <https://tukaani.org/xz/format.html>.
 
-- Compress a file:
+- Compress a file to the xz file format:
 
 `xz {{file}}`
 
-- Decompress a file:
+- Decompress a xz file:
 
 `xz -d {{file.xz}}`
 
+- Compress a file to the lzma file format:
+
+`xz --format=lzma {{file}}`
+
+- Decompress an lzma file:
+
+`xz -d --format=lzma {{file.lzma}}`
+
 - Decompress a file and write to stdout:
 
 `xz -dc {{file.xz}}`