docs: fix capitalization in doxygen comments

Change-Id: Ibf5ee5119d12d60d382b0acef8dfd08277c18fcb
diff --git a/daemon/fw/retx-suppression-fixed.hpp b/daemon/fw/retx-suppression-fixed.hpp
index fdd1114..7090b99 100644
--- a/daemon/fw/retx-suppression-fixed.hpp
+++ b/daemon/fw/retx-suppression-fixed.hpp
@@ -31,8 +31,9 @@
 
 namespace nfd::fw {
 
-/** \brief a retransmission suppression decision algorithm that
- *         suppresses retransmissions within a fixed duration
+/**
+ * \brief A retransmission suppression decision algorithm that
+ *        suppresses retransmissions within a fixed duration.
  */
 class RetxSuppressionFixed
 {
@@ -40,8 +41,8 @@
   explicit
   RetxSuppressionFixed(const time::milliseconds& minRetxInterval = DEFAULT_MIN_RETX_INTERVAL);
 
-  /** \brief determines whether Interest is a retransmission,
-   *         and if so, whether it shall be forwarded or suppressed
+  /** \brief Determines whether Interest is a retransmission,
+   *         and if so, whether it shall be forwarded or suppressed.
    */
   RetxSuppressionResult
   decidePerPitEntry(pit::Entry& pitEntry) const;