docs: document compression flags for commit and push

Signed-off-by: Jan Rodák <hony.com@seznam.cz>

Author: Honny1

docs/buildah-commit.1.md

@@ -135,6 +135,17 @@ image, to be used at run-time for retrieving the passphrase which was used to
 encrypt the disk image.  If not specified, a semi-random value will be derived
 from the base image's image ID.
 
+**--compression-format** *format*
+
+Specifies the compression format to use.  Supported values are: `gzip`, `zstd` and `zstd:chunked`.
+If not specified, the format is read from the `compression_format` setting in containers.conf.
+Cannot be used together with **--disable-compression**.
+
+**--compression-level** *level*
+
+Specifies the compression level to use.  The value is specific to the compression algorithm used, e.g. for zstd the accepted values are in the range 1-20 (inclusive), while for gzip it is 1-9 (inclusive).
+If not specified, the level is read from the `compression_level` setting in containers.conf.
+
 **--disable-compression**, **-D**
 
 Don't compress filesystem layers when building the image unless it is required
@@ -143,6 +154,7 @@ because image layers are compressed automatically when they are pushed to
 registries, and images being written to local storage would only need to be
 decompressed again to be stored.  Compression can be forced in all cases by
 specifying **--disable-compression=false**.
+Cannot be used together with **--compression-format** or **--force-compression**.
 
 **--encrypt-layer** *layer(s)*
 
@@ -152,6 +164,11 @@ Layer(s) to encrypt: 0-indexed layer indices with support for negative indexing
 
 The [protocol:keyfile] specifies the encryption protocol, which can be JWE (RFC7516), PGP (RFC4880), and PKCS7 (RFC2315) and the key material required for image encryption. For instance, jwe:/path/to/key.pem or pgp:admin@example.com or pkcs7:/path/to/x509-file.
 
+**--force-compression**
+
+If set, commit uses the specified compression algorithm even if the destination contains a differently-compressed variant already.
+Defaults to `true` if **--compression-format** is explicitly specified on the command-line or `compression_format` is set in containers.conf, `false` otherwise.
+
 **--format**, **-f** *[oci | docker]*
 
 Control the format for the image manifest and configuration data.  Recognized

docs/buildah-push.1.md

@@ -42,12 +42,12 @@ The default certificates directory is _/etc/containers/certs.d_.
 
 Specifies the compression format to use.  Supported values are: `gzip`, `zstd` and `zstd:chunked`.
 `zstd:chunked` is incompatible with encrypting images, and will be treated as `zstd` with a warning in that case.
+If not specified, the format is read from the `compression_format` setting in containers.conf.
 
 **--compression-level** *level*
 
-Specify the compression level used with the compression.
-
 Specifies the compression level to use.  The value is specific to the compression algorithm used, e.g. for zstd the accepted values are in the range 1-20 (inclusive), while for gzip it is 1-9 (inclusive).
+If not specified, the level is read from the `compression_level` setting in containers.conf.
 
 **--creds** *creds*
 
@@ -74,7 +74,7 @@ The [protocol:keyfile] specifies the encryption protocol, which can be JWE (RFC7
 **--force-compression**
 
 If set, push uses the specified compression algorithm even if the destination contains a differently-compressed variant already.
-Defaults to `true` if `--compression-format` is explicitly specified on the command-line, `false` otherwise.
+Defaults to `true` if `--compression-format` is explicitly specified on the command-line or `compression_format` is set in containers.conf, `false` otherwise.
 
 **--format**, **-f**