docs(lexarg): Include short help

Author: epage

crates/lexarg-error/examples/hello-error.rs

@@ -44,7 +44,7 @@ fn parse_args() -> Result<Args> {
                         .ok_or_else(|| ErrorContext::msg("invalid string").unexpected(arg))?,
                 );
             }
-            Long("help") => {
+            Short("h") | Long("help") => {
                 println!("Usage: hello [-n|--number=NUM] [--shout] THING");
                 std::process::exit(0);
             }

crates/lexarg/examples/hello.rs

@@ -30,7 +30,7 @@ fn parse_args() -> Result<Args, &'static str> {
             Value(val) if thing.is_none() => {
                 thing = Some(val.to_str().ok_or("invalid string")?);
             }
-            Long("help") => {
+            Short("h") | Long("help") => {
                 println!("Usage: hello [-n|--number=NUM] [--shout] THING");
                 std::process::exit(0);
             }