Spelling fixes

Spelling errors found using github.com/lucasdemarchi/codespell
A tool to fix common misspellings.
This tool is licensed under GNU General Public License, version 2.

Change-Id: Ia0a4d655510a1d5f81ac369bdad9f7cfbd675484
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/argument.hpp b/argument.hpp
index 51438b4..ad63cf9 100644
--- a/argument.hpp
+++ b/argument.hpp
@@ -23,7 +23,7 @@
         ArgumentParser(ArgumentParser&&) = default;
         ArgumentParser& operator=(ArgumentParser&&) = default;
 
-        /** @brief Contructs Argument object
+        /** @brief Constructs Argument object
          *
          *  @param argc - the main function's argc passed as is
          *  @param argv - the main function's argv passed as is