Add requires info to some args, fix a build error

Author: jessebraham

cargo-espflash/src/main.rs

@@ -254,8 +254,8 @@ fn build(
     // may not be immediately clear to the user.
     let cfg_has_build_std = cargo_config.has_build_std();
     let opts_has_build_std = build_options
-        .clone()
         .unstable
+        .clone()
         .map(|ref v| v.iter().any(|s| s.contains("build-std")))
         .unwrap_or_default();
     let xtensa_target = target.starts_with("xtensa-");

espflash/src/cli/mod.rs

@@ -113,10 +113,10 @@ pub struct SaveImageArgs {
     #[clap(long)]
     pub merge: bool,
     /// Custom partition table for merging
-    #[clap(long)]
+    #[clap(long, short = 'T', requires = "merge")]
     pub partition_table: Option<PathBuf>,
     /// Don't pad the image to the flash size
-    #[clap(long)]
+    #[clap(long, short = 'P', requires = "merge")]
     pub skip_padding: bool,
 }