[PATCH v2] docs: Makefile: Sort Documentation targets case-insensitively in make help

[Bhanu Seshu Kumar Valluri <bhanuseshukumar@gmail.com>]

Avoid case-sensitive sorting when listing Documentation targets in make help.
Previously, targets like PCI and RCU appeared ahead of others due to uppercase
names.

Normalize casing during _SPHINXDIRS generation to ensure consistent and
intuitive ordering.

Fixes: 965fc39f7393 ("Documentation: sort _SPHINXDIRS for 'make help'")
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bhanu Seshu Kumar Valluri <bhanuseshukumar@gmail.com>
---
 V1-V2 changes
 - Rebased on to commit 27600b51fbc8 ("MAINTAINERS: extend DOCUMENTATION SCRIPTS to the full directories")
   in docs-next.
 - Link to V1: https://lore.kernel.org/lkml/20251015012922.19467-1-bhanuseshukumar@gmail.com/

 Documentation/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 734ec9c9a..d514ab676 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -84,7 +84,7 @@ cleandocs:
 	$(Q)rm -rf $(BUILDDIR)
 
 # Used only on help
-_SPHINXDIRS   = $(sort $(patsubst $(srctree)/Documentation/%/index.rst,%,$(wildcard $(srctree)/Documentation/*/index.rst)))
+_SPHINXDIRS   = $(shell printf "%s\n" $(patsubst $(srctree)/Documentation/%/index.rst,%,$(wildcard $(srctree)/Documentation/*/index.rst)) | sort -f)
 
 dochelp:
 	@echo  ' Linux kernel internal documentation in different formats from ReST:'
-- 
2.34.1