docs: fix capitalization in doxygen comments

Change-Id: Ibf5ee5119d12d60d382b0acef8dfd08277c18fcb
diff --git a/daemon/face/socket-utils.hpp b/daemon/face/socket-utils.hpp
index 9efb389..2b358e9 100644
--- a/daemon/face/socket-utils.hpp
+++ b/daemon/face/socket-utils.hpp
@@ -30,7 +30,7 @@
 
 namespace nfd::face {
 
-/** \brief obtain send queue length from a specified system socket
+/** \brief Obtain send queue length from a specified system socket.
  *  \param fd file descriptor of the socket
  *  \retval QUEUE_UNSUPPORTED this operation is unsupported on the current platform
  *  \retval QUEUE_ERROR there was an error retrieving the send queue length