doc: Fix case in titles

Unified case in titles.
Fixed small grammar issues.

Signed-off-by: Francesco Servidio <francesco.servidio@nordicsemi.no>
diff --git a/docs/SubmittingPatches.md b/docs/SubmittingPatches.md
index 5d19c51..37f908c 100644
--- a/docs/SubmittingPatches.md
+++ b/docs/SubmittingPatches.md
@@ -1,4 +1,4 @@
-# Submitting Patches
+# Submitting patches
 
 Development on MCUboot primarily takes place in github, at:
 https://github.com/mcu-tools/mcuboot
@@ -27,7 +27,7 @@
 putting them in a trailer with a common format will make them easier
 to find later.
 
-# Developer Certificate of Origin
+# Developer certificate of origin
 
 ```
 Developer Certificate of Origin