zstd, zstdmt, zstdcat: standardize alias, add example and fix alias

pages/common/zstd.md

@@ -26,3 +26,7 @@
 - Unlock higher compression levels (up to 22) using more memory (both for compression and decompression):
 
 `zstd --ultra -{{level}} {{path/to/file}}`
+
+- Set the number of working threads to the number of physical CPU cores:
+
+`zstd {{[-T|--threads]}} 0`

pages/common/zstdcat.md

@@ -1,6 +1,6 @@
 # zstdcat
 
-> This command is an alias of `zstd --decompress --stdout`.
+> This command is an alias of `zstd --decompress --stdout --force`.
 
 - View documentation for the original command:
 

pages/common/zstdmt.md

@@ -1,6 +1,6 @@
 # zstdmt
 
-> This command is an alias of `zstd --threads 0` (which sets the number of working threads to the number of physical CPU cores).
+> This command is an alias of `zstd --threads 0`.
 
 - View documentation for the original command: