docs: Remove space-before-label guidance from CodingStyle

Recent discussion has made it clear that there is no community consensus on
this particular rule.  Remove it now, lest it inspire yet another set of
unwanted "cleanup" patches.

This partially reverts 865a1caa (CodingStyle: Clarify and complete
chapter 7).

Cc: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/CodingStyle

@@ -451,9 +451,6 @@ Avoid using GW-BASIC names like ``err1:`` and ``err2:``, as you would have to
 renumber them if you ever add or remove exit paths, and they make correctness
 difficult to verify anyway.
 
-It is advised to indent labels with a single space (not tab), so that
-``diff -p`` does not confuse labels with functions.
-
 The rationale for using gotos is:
 
 - unconditional statements are easier to understand and follow