Add documentation to types

index.d.ts

@@ -443,20 +443,31 @@ export type ExecaChildPromise<StdoutStderrType extends StdoutStderrAll> = {
  cancel(): void;
 
  /**
+ [Pipe](https://nodejs.org/api/stream.html#readablepipedestination-options) the child process's `stdout` to `target`, which can be:
+ - Another `execa()` return value
+ - A writable stream
+ - A file path string
 
- */
+ If the `target` is another `execa()` return value, it is returned. Otherwise, the original `execa()` return value is returned. This allows chaining `pipeStdout()` then `await`ing the final result.
+
+ The `stdout` option] must be kept as `pipe`, its default value.
+ */
  pipeStdout?<Target extends ExecaChildPromise<StdoutStderrAll>>(target: Target): Target;
  pipeStdout?(target: WritableStream | string): ExecaChildProcess<StdoutStderrType>;
 
  /**
+ Like `pipeStdout()` but piping the child process's `stderr` instead.
 
- */
+ The `stderr` option must be kept as `pipe`, its default value.
+ */
  pipeStderr?<Target extends ExecaChildPromise<StdoutStderrAll>>(target: Target): Target;
  pipeStderr?(target: WritableStream | string): ExecaChildProcess<StdoutStderrType>;
 
  /**
+ Combines both `pipeStdout()` and `pipeStderr()`.
 
- */
+ Either the `stdout` option or the `stderr` option must be kept as `pipe`, their default value. Also, the `all` option must be set to `true`.
+ */
  pipeAll?<Target extends ExecaChildPromise<StdoutStderrAll>>(target: Target): Target;
  pipeAll?(target: WritableStream | string): ExecaChildProcess<StdoutStderrType>;
 };