[#3726] Typo in preface (#4377)

* [#3726] Typo in preface

Signed-off-by: Miguel Serra <Miguel.Serra@criticaltechworks.com>

docs/src/main/docbook/sse.xml

diff --git a/docs/src/main/docbook/sse.xml b/docs/src/main/docbook/sse.xml
index ddb2f11..b59a0e8 100644
--- a/docs/src/main/docbook/sse.xml
+++ b/docs/src/main/docbook/sse.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!--
 
-    Copyright (c) 2012, 2019 Oracle and/or its affiliates. All rights reserved.
+    Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
 
     This program and the accompanying materials are made available under the
     terms of the Eclipse Public License v. 2.0, which is available at

docs/src/main/docbook/user-guide.xml

diff --git a/docs/src/main/docbook/user-guide.xml b/docs/src/main/docbook/user-guide.xml
index 2922be7..fc1dbf2 100644
--- a/docs/src/main/docbook/user-guide.xml
+++ b/docs/src/main/docbook/user-guide.xml
@@ -59,7 +59,7 @@
             </para>
             <para>
                 <emphasis>Emphasised font</emphasis>
-                is used to a call attention to a newly introduce concept, when it first
+                is used to call attention to a newly introduce concept, when it first
                 occurs in the text.
             </para>
             <para>