docs: Don't use backslashes in command blocks
Advise authors not to use continuation characters in code blocks.
Fixes
@@ -100,6 +100,14 @@ utility.
```
+- Long lines should not span across multiple lines by using the '`\`'
+ continuation character.
+
+ GitHub automatically renders such blocks with scrollbars. Consequently,
+ backslash continuation characters are not necessary and are a visual
+ distraction. These characters also mess up a user's shell history when
+ commands are pasted into a terminal.
+
# Images
All binary image files must be in a standard and well-supported format such as
