[PATCH] Makefile: List the sphinx documentation in 'make help'

[Philippe Mathieu-Daudé]

In commit 5f71eac06e1 we started to support the rST documentation.
List the build target we need to call to generate the rST files in
the 'make help' output.

Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 6562b0dc97..b777f7fcdd 100644
--- a/Makefile
+++ b/Makefile
@@ -1197,7 +1197,7 @@ endif
        @echo  '  vm-help         - Help about targets running tests inside VM'
        @echo  ''
        @echo  'Documentation targets:'
-       @echo  '  html info pdf txt'
+       @echo  '  html info pdf txt sphinxdocs'
        @echo  '                  - Build documentation in specified format'
 ifdef CONFIG_GCOV
        @echo  '  coverage-report - Create code coverage report'
-- 
2.21.1