Don't specify multiple_occurences, it's redundant

- Setting `multiple_occurences` for an argument whose type is
    `Vec<_>` is redundant; clap infers it from the type.

src/sq_cli/encrypt.rs

@@ -42,14 +42,12 @@ pub struct Command {
     #[clap(
         long = "recipient-cert",
         value_name = "FINGERPRINT|KEYID",
-        multiple_occurrences = true,
         help = "Encrypts to the named certificates",
     )]
     pub recipients_cert: Vec<KeyHandle>,
     #[clap(
         long = "recipient-file",
         value_name = "CERT_RING_FILE",
-        multiple_occurrences = true,
         help = "Encrypts to all certificates in CERT_RING_FILE",
     )]
     pub recipients_file: Vec<String>,
@@ -69,7 +67,6 @@ pub struct Command {
         short = 's',
         long = "symmetric",
         help = "Adds a password to encrypt with",
-        multiple_occurrences = true,
         long_help = "Adds a password to encrypt with.  \
             The message can be decrypted with \
             either one of the recipient's keys, or any password.",

src/sq_cli/export.rs

@@ -65,7 +65,6 @@ pub struct Command {
     #[clap(
         long = "cert",
         value_name = "FINGERPRINT|KEYID",
-        multiple_occurrences = true,
         help = "Returns certificates that \
                 have the specified fingerprint or key ID",
     )]
@@ -74,7 +73,6 @@ pub struct Command {
     #[clap(
         long = "key",
         value_name = "FINGERPRINT|KEYID",
-        multiple_occurrences = true,
         help = "Returns certificates where the primary key or \
                 a subkey has the specified fingerprint or key ID",
     )]
@@ -83,7 +81,6 @@ pub struct Command {
     #[clap(
         long = "userid",
         value_name = "USERID",
-        multiple_occurrences = true,
         help = "Returns certificates that have a User ID that \
                 matches exactly, including case",
     )]
@@ -92,7 +89,6 @@ pub struct Command {
     #[clap(
         long = "grep",
         value_name = "PATTERN",
-        multiple_occurrences = true,
         help = "Returns certificates that have a User ID that \
                 contains the string, case insensitively",
     )]
@@ -101,7 +97,6 @@ pub struct Command {
     #[clap(
         long = "email",
         value_name = "EMAIL",
-        multiple_occurrences = true,
         help = "Returns certificates that have a User ID with \
                 the specified email address, case insensitively",
     )]
@@ -110,7 +105,6 @@ pub struct Command {
     #[clap(
         long = "domain",
         value_name = "DOMAIN",
-        multiple_occurrences = true,
         help = "Returns certificates that have a User ID with \
                 an email address from the specified domain",
     )]

src/sq_cli/keyring.rs

@@ -87,7 +87,6 @@ pub struct FilterCommand {
     #[clap(
         long = "userid",
         value_name = "USERID",
-        multiple_occurrences = true,
         help = "Matches on USERID",
         long_help = "Case-sensitively matches on the \
                 user id, requiring an exact match.",
@@ -96,7 +95,6 @@ pub struct FilterCommand {
     #[clap(
         long = "name",
         value_name = "NAME",
-        multiple_occurrences = true,
         help = "Matches on NAME",
         long_help = "Parses user ids into name and email \
             and case-sensitively matches on the \
@@ -106,7 +104,6 @@ pub struct FilterCommand {
     #[clap(
         long = "email",
         value_name = "ADDRESS",
-        multiple_occurrences = true,
         help = "Matches on email ADDRESS",
         long_help = "Parses user ids into name and email \
             address and case-sensitively matches \

src/sq_cli/mod.rs

@@ -115,7 +115,6 @@ and creates it if it does not exist."
     #[clap(
         long = "known-notation",
         value_name = "NOTATION",
-        multiple_occurrences = true,
         help = "Adds NOTATION to the list of known notations",
         long_help = "Adds NOTATION to the list of known notations. \
             This is used when validating signatures. \