tweaks: a comma does not end a sentence, and is not part of a variable

NEWS

@@ -307,7 +307,7 @@
 		many many improvements to the core system, including
 		substantial improvements to the undo/redo code, UTF-8
 		handling, the configure script, and display of shortcuts
-		on very wide terminals,  New features include the
+		on very wide terminals.  New features include the
 		ability to write to named pipes (--noread), as well as
 		linter support (see the nanorc man page for details).  Also
 		included are much improved syntax highlighting code, and

doc/nano.texi

@@ -744,7 +744,7 @@ Valid names for foreground and background color are:
 @code{white}, @code{black}, @code{blue}, @code{green},
 @code{red}, @code{cyan}, @code{yellow}, and @code{magenta}.
 The name of the foreground color may be prefixed with @code{bright}.
-And either @var{fgcolor} or @var{,bgcolor} may be left out.
+And either @var{fgcolor} or ,@var{bgcolor} may be left out.
 
 @item set historylog
 Enable the use of @file{~/.nano/search_history} for saving and reading