Update documentation to reflect addition of `clean` subcommand. (#607)

* update documentation

Update README.md and User Guide to reflect addition of `clean`
subcommand. Do minor spelling fixes too.

* fix grammar in `clean` documentation

README.md

@@ -141,6 +141,10 @@ explanation, check out the [User Guide].
     `http://localhost:3000` (port is changeable) and reloads the browser when a
     change occurs.
 
+- `mdbook clean`
+
+    Delete directory in which generated book is located.
+
 
 ### As a library
 

book-example/src/SUMMARY.md

@@ -7,6 +7,7 @@
     - [watch](cli/watch.md)
     - [serve](cli/serve.md)
     - [test](cli/test.md)
+    - [clean](cli/clean.md)
 - [Format](format/format.md)
     - [SUMMARY.md](format/summary.md)
     - [Configuration](format/config.md)

book-example/src/cli/build.md

@@ -14,8 +14,8 @@ convenience. Large books will therefore remain structured when rendered.
 
 #### Specify a directory
 
-Like `init`, the `build` command can take a directory as argument to use instead of the
-current working directory.
+Like `init`, the `build` command can take a directory as an argument to use
+instead of the current working directory.
 
 ```bash
 mdbook build path/to/book

book-example/src/cli/clean.md

@@ -0,0 +1,21 @@
+# The clean command
+
+The clean command is used to delete the generated book and any other build
+artifacts.
+
+```bash
+mdbook clean
+```
+
+It will try to delete the built book. If a path is provided, it will be used.
+
+#### Specify a directory
+
+Like `init`, the `clean` command can take a directory as an argument to use
+instead of the normal build directory.
+
+```bash
+mdbook clean --dest-dir=path/to/book
+```
+
+`path/to/book` could be absolute or relative.

book-example/src/cli/serve.md

@@ -6,8 +6,8 @@ This preferred by many for writing books with mdbook because it allows for you t
 
 #### Specify a directory
 
-Like `watch`, `serve` can take a directory as argument to use instead of the
-current working directory.
+Like `watch`, `serve` can take a directory as an argument to use instead of
+the current working directory.
 
 ```bash
 mdbook serve path/to/book

book-example/src/cli/watch.md

@@ -5,8 +5,8 @@ You could repeatedly issue `mdbook build` every time a file is changed. But usin
 
 #### Specify a directory
 
-Like `init` and `build`, `watch` can take a directory as argument to use instead of the
-current working directory.
+Like `init` and `build`, `watch` can take a directory as an argument to use
+instead of the current working directory.
 
 ```bash
 mdbook watch path/to/book