plugins/bashmarks: Format README

plugins/bashmarks/README.md

@@ -1,26 +1,45 @@
 # Bashmarks plugin
 
-The Bashmarks plugin allows you to create and use bookmarks for directories on your filesystems.
+The Bashmarks plugin allows you to create and use bookmarks for directories on
+your filesystems.
 
 ## Quickstart
 
 Create a new bookmark using the *bm -a* command:
 
-`$ bm -a mydir`
+```bash
+$ bm -a mydir
+```
 
-The command above creates a bookmark for the current directory with the name *mydir*.
+The command above creates a bookmark for the current directory with the name
+*mydir*.
 
 You can navigate to the location of a bookmark using the *bm -g* command:
 
-`$ bm -g mydir`
+```bash
+$ bm -g mydir
+```
 
 You can also supply just any bookmark name and the *-g* option will be assumed:
 
-`$ bm mydir`
+```bash
+$ bm mydir
+```
 
-Tab completion is available when you need to enter a bookmark name in a command, such as when using *bm -g*
+Tab completion is available when you need to enter a bookmark name in a
+command, such as when using *bm -g*
 
-Easily list all bookmarks you have setup using the *bm -l* command.
+Easily list all bookmarks you have set up using the *bm -l* command:
+
+```bash
+$ bm -l
+```
+
+## Configuration
+
+- **`BASHMARKS_SDIR`**: This variable contains the path to the file that stores
+  the information of bookmarks of directory names. The default path is
+  `~/.sdirs`.  The old interface `SDIRS` is now deprecated.
 
 ## Commands
 
@@ -38,4 +57,6 @@ Easily list all bookmarks you have setup using the *bm -l* command.
 
 ## Valid bookmark names
 
-A bookmark name can contain lower and upper case characters (A-Z), numbers and underscore characters. No periods, semicolons, spaces or other characters are allowed in a bookmark name.
+A bookmark name can contain lower and upper case characters (A-Z), numbers and
+underscore characters. No periods, semicolons, spaces or other characters are
+allowed in a bookmark name.