unzstd: add page (#8385)

pages/common/unzstd.md

@@ -0,0 +1,16 @@
+# unzstd
+
+> Decompress files with Zstandard compression.
+> More information: <https://github.com/facebook/zstd>.
+
+- Decompress files:
+
+`unzstd {{path/to/file1.ztd path/to/file2.ztd ...}}`
+
+- Decompress a file into a specific output file:
+
+`unzstd {{path/to/compressed.ztd}} -o {{path/to/extracted_file}}`
+
+- Display information about a compressed file:
+
+`unzip --list {{path/to/file.zst}}`