Tweak `js` a little, mainly for 80 columns

sheets/js

@@ -1,18 +1,19 @@
 # js
 #
-# JavaScript often abbreviated as "JS", is a high-level, dynamic, untyped, interpreted run-time language.
+# JavaScript often abbreviated as "JS", is a high-level, dynamic, untyped, -
-# It has been standardized in the ECMAScript language specification.
+# interpreted run-time language. It has been standardized in the ECMAScript
+# language specification.
 #
-# js is a JavaScript shell, part of SpiderMonkey
+# `js` is a JavaScript shell, part of SpiderMonkey. To install spidermonkey in
-# to install spidermonkey: (in Debian) apt-get install libmozjs-24-bin
+# Debian systems, execute: apt-get install libmozjs-24-bin
 
-# Run the shell in interactive mode
+# Launch an interactive JavaScript session.
 js
 
-# Run the JavaScript code in the file hello.js
+# Run the JavaScript code in the file `hello.js`.
 js hello.js
 
-# Run hello.js then drop into the interactive shell
+# Run the `hello.js` file, then drop into the interactive shell.
 js -f hello.js -i
 
 # See also: