fix: Windows Multicall support

The executable suffix is unconditionally stripped off the file path
so that the file name matches subcommands names
without having to add the EXE suffix on different platforms.

examples/multicall_busybox.md

@@ -6,7 +6,7 @@ See the documentation for clap::AppSettings::Multicall for rationale.
 
 This example omits every command except true and false,
 which are the most trivial to implement,
-```bash,ignore
+```bash
 $ busybox true
 ? 0
 $ busybox false
@@ -16,20 +16,20 @@ $ busybox false
 
 But includes the `--install` option as an example of why it can be useful
 for the main program to take arguments that aren't applet subcommands.
-```bash,ignore
+```bash
 $ busybox --install
 ? failed
 ...
 ```
 
 Though users must pass something:
-```bash,ignore
+```bash
 $ busybox
 ? failed
 busybox 
 
 USAGE:
-    busybox[EXE] [OPTIONS] [APPLET]
+    busybox [OPTIONS] [APPLET]
 
 OPTIONS:
     -h, --help                 Print help information

examples/multicall_hostname.md

@@ -6,7 +6,7 @@ See the documentation for clap::AppSettings::Multicall for rationale.
 
 This example omits the implementation of displaying address config
 
-```bash,ignore
+```bash
 $ hostname
 www
 ```

src/build/app/mod.rs

@@ -607,7 +607,7 @@ impl<'help> App<'help> {
         if self.settings.is_set(AppSettings::Multicall) {
             if let Some((argv0, _)) = it.next() {
                 let argv0 = Path::new(&argv0);
-                if let Some(command) = argv0.file_name().and_then(|f| f.to_str()) {
+                if let Some(command) = argv0.file_stem().and_then(|f| f.to_str()) {
                     // Stop borrowing command so we can get another mut ref to it.
                     let command = command.to_owned();
                     debug!(