docs: Fix a typo

docs/usermanual-object-model.xml

@@ -12,7 +12,7 @@
       HarfBuzz features two kinds of data types: non-opaque,
       pass-by-value types and opaque, heap-allocated types.  This kind
       of separation is common in C libraries that have to provide
-      API/ABI compatibility (almost) indefinitely. 
+      API/ABI compatibility (almost) indefinitely.
     </para>
     <para>
       <emphasis>Value types:</emphasis> The non-opaque, pass-by-value
@@ -32,8 +32,8 @@
       possible future members.  As such, it’s important to provide
       <function>equal()</function>, and <function>hash()</function>
       methods for such structs, allowing users of the API do
-      effectively deal with the type without having to 
-      adapt their code to future changes. 
+      effectively deal with the type without having to
+      adapt their code to future changes.
     </para>
     <para>
       Important value types provided by HarfBuzz include the structs
@@ -42,7 +42,7 @@
       OpenType properties.
     </para>
   </section>
-  
+
   <section id="object-model-object-types">
     <title>Objects in HarfBuzz</title>
     <para>
@@ -63,7 +63,7 @@
       the <literal>hb_buffer_t</literal> object has
       <function>hb_buffer_create()</function> as its constructor,
       <function>hb_buffer_reference()</function> to reference, and
-      <function>hb_buffer_destroy()</function> to dereference. 
+      <function>hb_buffer_destroy()</function> to dereference.
     </para>
     <para>
       After construction, each object's properties are accessible only
@@ -110,11 +110,11 @@
 	</para>
       </listitem>
     </itemizedlist>
-	
+
   </section>
 
-  
-  
+
+
   <section id="object-model-lifecycle">
     <title>Object lifecycle management</title>
     <para>
@@ -131,7 +131,7 @@
       <literal>1</literal>. Client programs can increase the reference
       count on an object by calling its
       <function>reference()</function> method. Whenever a client
-      program is finished with an object, it should call its 
+      program is finished with an object, it should call its
       corresponding <function>destroy()</function> method. The destroy
       method will decrease the reference count on the object and,
       whenever the reference count reaches zero, it will also destroy
@@ -141,8 +141,8 @@
       All of HarfBuzz's object-lifecycle-management APIs are
       thread-safe (unless you compiled HarfBuzz from source with the
       <literal>HB_NO_MT</literal> configuration flag), even when the
-      object as a whole is not thread-safe. 
-      It is also permissible to <function>reference()</function> or to 
+      object as a whole is not thread-safe.
+      It is also permissible to <function>reference()</function> or to
       <function>destroy()</function> the <literal>NULL</literal>
       value.
     </para>
@@ -160,7 +160,7 @@
       as immutable and <function>is_immutable()</function> methods to
       test whether or not an object is immutable. Attempts to use
       setter functions on immutable objects will fail silently; see the API
-      Reference manual for specifics. 
+      Reference manual for specifics.
     </para>
     <para>
       Note also that there are no "make mutable" methods. If client
@@ -187,7 +187,7 @@
     </para>
   </section>
 
-  
+
   <section id="object-model-user-data">
     <title>User data</title>
     <para>
@@ -195,7 +195,7 @@
       offer a "user data" mechanism that can be used to attach
       arbitrary data to the object.  User-data attachment can be
       useful for tying the lifecycles of various pieces of data
-      together, or for creating language bindings. 
+      together, or for creating language bindings.
     </para>
     <para>
       Each object type has a <function>set_user_data()</function>
@@ -220,10 +220,10 @@
       existing <literal>user_data</literal>
       associated with the specified key.
     </para>
-  </section>  
+  </section>
+
+
 
-  
-  
   <section id="object-model-blobs">
     <title>Blobs</title>
     <para>
@@ -238,9 +238,9 @@
       you do so in a <literal>hb_blob_t</literal> wrapper.
     </para>
     <para>
-      This allows you to take advantage of HarffBuzz's
+      This allows you to take advantage of HarfBuzz's
       reference-counting and <function>destroy</function>
-      callbacks. If you allocated the memory for the data using 
+      callbacks. If you allocated the memory for the data using
       <function>malloc()</function>, you would create the blob using
     </para>
     <programlisting language="C">
@@ -251,8 +251,8 @@
       allocated memory whenever the blob drops its last reference and
       is deconstructed.  Consequently, the user code can stop worrying
       about freeing memory and let the reference-counting machinery
-      take care of that. 
+      take care of that.
     </para>
   </section>
-  
+
 </chapter>