Fix typos in comments and doc

overriden -> overridden

The misspelling in create_extension.sgml was introduced in b67aaf2,
so no need to backpatch.

doc/src/sgml/ref/create_extension.sgml

@@ -97,7 +97,7 @@ CREATE EXTENSION [ IF NOT EXISTS ] <replaceable class="parameter">extension_name
        </para>
        <para>
         If the extension specifies <literal>schema</> in its control file,
-        the schema cannot be overriden with <literal>SCHEMA</> clause.
+        the schema cannot be overridden with <literal>SCHEMA</> clause.
         The <literal>SCHEMA</> clause in this case works as follows:
         <itemizedlist>
          <listitem>

src/backend/bootstrap/bootstrap.c

@@ -204,7 +204,7 @@ AuxiliaryProcessMain(int argc, char *argv[])
 	 * process command arguments
 	 */
 
-	/* Set defaults, to be overriden by explicit options below */
+	/* Set defaults, to be overridden by explicit options below */
 	if (!IsUnderPostmaster)
 		InitializeGUCOptions();
 

src/makefiles/Makefile.win32

@@ -44,7 +44,7 @@ override CPPFLAGS+= -DUSE_DL_IMPORT
 endif
 
 # it is better to install shared-libraries anyway?
-# may be overriden with make MAKE_DLL=false install
+# may be overridden with make MAKE_DLL=false install
 ifndef MAKE_DLL
 MAKE_DLL	= true
 endif