Some minor doc cleanups and tweaks.

doc/site/core/io.markdown

@@ -5,7 +5,7 @@ The IO class can be used to read and write to and from the console.
 
 ## Static Methods
 
-### IO.print(obj[, obj2, obj3...])
+### IO.**print**(objects...)
 
 Prints any number of things to the console and then prints a newline
 character. If you don't pass it a string, it will be converted to a string for
@@ -16,21 +16,21 @@ you. When passed multiple things, Wren outputs one after another.
 	I like bananas
 	> IO.print("Oranges", 10)
 	Oranges10
-	> 
+	>
 
-### IO.write(obj)
+### IO.**write**(object)
 
 Prints a single thing to the console, but does not print a newline character
 afterwards. If you pass it something that isn't a string, it will convert it to
 a string.
 
-	> IO.write(4+5)
+	> IO.write(4 + 5)
 	9>
 
-In the above example, the result of `4+5` is printed, and then the prompt is
+In the above example, the result of `4 + 5` is printed, and then the prompt is
 printed on the same line because no newline character was printed afterwards.
 
-### IO.read(prompt)
+### IO.**read**(prompt)
 
 Reads in and returns a line of text from the console. Takes a single string to
 be used as a prompt. Pass an empty string for no prompt. Note that the returned
@@ -41,4 +41,4 @@ line of text includes the newline character at the end.
 	> IO.print("Hello " + name + "!")
 	Hello John
 	!
-	> 
+	>