Fixes issues from #58 (Windows-specific)

- Uses a more sensible default of notepad.exe on Windows
- Changes the tempfile name to have "renamer-" prefix and ".txt" suffix
  (the latter being a workaround for Windows which doesn't handle file
  names with a leading dot too well in Notepad)
- Updated README file to mention the new option

README.md

@@ -47,13 +47,28 @@ USAGE:
 ARGS:
     <FILES>...
 
+
 OPTIONS:
-    -c, --rename-command <RENAME_COMMAND>    Optionally set a custom rename command, like 'git mv'
-    -f, --force                              Overwrite existing files
-    -h, --help                               Print help information
-    -p, --pretty-diff                        Prettify diffs
-    -V, --version                            Print version information
-    -y, --yes                                Answer all prompts with yes
+    -c, --rename-command <COMMAND>
+            Optionally set a custom rename command, like 'git mv'
+
+    -e, --editor <EDITOR>
+            Optionally set an editor, overriding EDITOR environment variable and default
+
+    -f, --force
+            Overwrite existing files
+
+    -h, --help
+            Print help information
+
+    -p, --pretty-diff
+            Prettify diffs
+
+    -V, --version
+            Print version information
+
+    -y, --yes
+            Answer all prompts with yes
 ```
 
 ## Contributors ✨

src/main.rs

@@ -197,7 +197,11 @@ fn expand_dir(path: &str) -> anyhow::Result<Vec<String>, io::Error> {
 }
 
 fn open_editor(input_files: &[String], editor_string: &str) -> anyhow::Result<Vec<String>> {
-    let mut tmpfile = tempfile::NamedTempFile::new().context("Could not create temp file")?;
+    let mut tmpfile = tempfile::Builder::new()
+        .prefix("renamer-")
+        .suffix(".txt")
+        .tempfile()
+        .context("Could not create temp file")?;
     write!(tmpfile, "{}", input_files.join("\n"))?;
     let editor_parsed = shell_words::split(editor_string)
         .expect("failed to parse command line flags in EDITOR command");
@@ -344,11 +348,12 @@ fn main() -> anyhow::Result<()> {
 
     check_input_files(&input_files)?;
 
+    let default_editor = if cfg!(windows) { "notepad.exe" } else { "vim" };
+    let default_editor = default_editor.to_string();
     let editor = opts.editor
         .unwrap_or_else(
             || env::var("EDITOR")
-            .unwrap_or_else(
-                |_| "vim".to_string()));
+            .unwrap_or(default_editor));
     let mut buffer = input_files.clone();
 
     loop {