rust/pvattest: Add short option for --arpk

pvattest-C had a -a option for --arpk which the Rust implementation
missed.
Add this short option.

Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>

rust/pvattest/man/pvattest-create.1

@@ -75,7 +75,7 @@ Write the generated request to FILE.
 .RE
 .RE
 .PP
-\-\-arpk <FILE>
+\-a, \-\-arpk <FILE>
 .RS 4
 Save the protection key as unencrypted GCM-AES256 key in FILE Do not publish
 this key, otherwise your attestation is compromised.

rust/pvattest/man/pvattest-verify.1

@@ -45,7 +45,7 @@ must start at a page boundary.
 .RE
 .RE
 .PP
-\-\-arpk <FILE>
+\-a, \-\-arpk <FILE>
 .RS 4
 Use FILE as the protection key to decrypt the request Do not publish this key,
 otherwise your attestation is compromised. Delete this key after verification.

rust/pvattest/src/cli.rs

@@ -97,7 +97,7 @@ pub struct CreateAttOpt {
     /// Save the protection key as unencrypted GCM-AES256 key in FILE
     ///
     /// Do not publish this key, otherwise your attestation is compromised.
-    #[arg(long, value_name = "FILE", value_hint = ValueHint::FilePath,)]
+    #[arg(short, long, value_name = "FILE", value_hint = ValueHint::FilePath,)]
     pub arpk: String,
 
     /// Specify-additional data for the request.
@@ -222,7 +222,7 @@ pub struct VerifyOpt {
     ///
     /// Do not publish this key, otherwise your attestation is compromised.
     /// Delete this key after verification.
-    #[arg(long, value_name = "FILE", value_hint = ValueHint::FilePath,)]
+    #[arg(short, long, value_name = "FILE", value_hint = ValueHint::FilePath,)]
     pub arpk: String,
 
     /// Define the output format.