Misc-typos (#741)

Found in downstream CMake repo via `codespell -q 3`
diff --git a/include/json/config.h b/include/json/config.h
index 9410449..7d34692 100644
--- a/include/json/config.h
+++ b/include/json/config.h
@@ -80,7 +80,7 @@
 
 // In c++11 the override keyword allows you to explicitly define that a function
 // is intended to override the base-class version.  This makes the code more
-// managable and fixes a set of common hard-to-find bugs.
+// manageable and fixes a set of common hard-to-find bugs.
 #if __cplusplus >= 201103L
 # define JSONCPP_OVERRIDE override
 # define JSONCPP_NOEXCEPT noexcept
diff --git a/include/json/writer.h b/include/json/writer.h
index 2278bc8..9e7adde 100644
--- a/include/json/writer.h
+++ b/include/json/writer.h
@@ -152,7 +152,7 @@
  *
  * The JSON document is written in a single line. It is not intended for 'human'
  *consumption,
- * but may be usefull to support feature such as RPC where bandwith is limited.
+ * but may be useful to support feature such as RPC where bandwidth is limited.
  * \sa Reader, Value
  * \deprecated Use StreamWriterBuilder.
  */