fix typos and docs in GlobalError documentation

Reported-By: Manuel A. Fernandez Montecelo <mafm@debian.org>
Git-Dch: Ignore

apt-pkg/contrib/error.h

@@ -148,7 +148,7 @@ public:									/*{{{*/
 	 *  Most of the stuff we consider as "error" is also "fatal" for
 	 *  the user as the application will not have the expected result,
 	 *  but a fatal message here means that it gets printed directly
-	 *  to stderr in addiction to adding it to the list as the error
+	 *  to stderr in addition to adding it to the list as the error
 	 *  leads sometimes to crashes and a maybe duplicated message
 	 *  is better than "Segfault" as the only displayed text
 	 *
@@ -229,13 +229,13 @@ public:									/*{{{*/
 
 	/** \brief is the list empty?
 	 *
-	 *  The default checks if the list is empty or contains only notices,
-	 *  if you want to check if also no notices happened set the parameter
-	 *  flag to \b false.
+	 *  Can be used to check if the current stack level doesn't include
+	 *  anything equal or more severe than a given threshold, defaulting
+	 *  to warning level for historic reasons.
 	 *
-	 *  \param threshold minimim level considered
+	 *  \param threshold minimum level considered
 	 *
-	 *  \return \b true if an the list is empty, \b false otherwise
+	 *  \return \b true if the list is empty, \b false otherwise
 	 */
 	bool empty(MsgType const &threshold = WARNING) const APT_PURE;
 
@@ -252,12 +252,11 @@ public:									/*{{{*/
 
 	/** \brief outputs the list of messages to the given stream
 	 *
-	 *  Note that all messages are discarded, also the notices
-	 *  displayed or not.
+	 *  Note that all messages are discarded, even undisplayed ones.
 	 *
 	 *  \param[out] out output stream to write the messages in
-	 *  \param threshold minimim level considered
-         *  \param mergeStack 
+	 *  \param threshold minimum level considered
+	 *  \param mergeStack if true recursively dumps the entire stack
 	 */
 	void DumpErrors(std::ostream &out, MsgType const &threshold = WARNING,
 			bool const &mergeStack = true);