Extend the shell-scripting section of CodingGuidelines to suggest octal
escape sequences (e.g. "\302\242") over hexadecimal (e.g. "\xc2\xa2")
since the latter can be a source of portability problems.

Signed-off-by: Jonathan Tan <redacted>
---
I've used Eric's suggestion for the commit message and limited the scope
of the documentation change to printf.

Version 1 was here:
https://lore.kernel.org/git/20230613172927.19019-1-jonathantanmy@google.com/ (local)
---
 Documentation/CodingGuidelines | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 003393ed16..30ac7d2d3f 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines

@@ -188,6 +188,10 @@ For shell scripts specifically (not exhaustive):
    hopefully nobody starts using "local" before they are reimplemented
    in C ;-)
 
+ - Use octal escape sequences (e.g. "\302\242"), not hexadecimal (e.g.
+   "\xc2\xa2"), since the latter is not portable across commands like
+   "printf".