Document library interface (#2174)

src/lib.rs

@@ -13,6 +13,12 @@
   overlapping_range_endpoints
 )]
 
+//! `just` is primarily used as a command-line binary, but does provide a
+//! limited public library interface.
+//!
+//! Please keep in mind that there are no semantic version guarantees for the
+//! library interface. It may break or change at any time.
+
 pub(crate) use {
   crate::{
     alias::Alias, analyzer::Analyzer, argument_parser::ArgumentParser, assignment::Assignment,

src/run.rs

@@ -1,6 +1,7 @@
 use super::*;
 
-/// Main entry point into just binary.
+/// Main entry point into `just`. Parse arguments from `args` and run. `run()`
+/// will exit the proceess if `args` cannot be parsed.
 #[allow(clippy::missing_errors_doc)]
 pub fn run(args: impl Iterator<Item = impl Into<OsString> + Clone>) -> Result<(), i32> {
   #[cfg(windows)]