added release.txt blurb. Fixed spelling typo in Defaults.xml

Author: bdbaddog

RELEASE.txt

@@ -63,6 +63,9 @@ DOCUMENTATION
 -------------
 
 - Improve wording of manpage "Functions and Environment Methods" section.
+- Make doc function signature style more consistent - tweaks to AddOption,
+  DefaultEnvironment and Tool,.
+
 
 DEVELOPMENT
 -----------

SCons/Defaults.xml

@@ -758,7 +758,7 @@ either existing or newly constructed.
 </para>
 
 <para>
-It is not necessary to explcitly call &f-DefaultEnvironment;.
+It is not necessary to explicitly call &f-DefaultEnvironment;.
 &SCons; instantiates the &defenv; automatically when the
 build phase begins, if has not already been done.
 However, calling it explicitly provides the opportunity to