doc: Shorten some long subsection names in Manual. Remove excess spaces from ends of @menu definitions. * doc/interpreter/arith.txi, doc/interpreter/basics.txi, doc/interpreter/bugs.txi, doc/interpreter/container.txi, doc/interpreter/data.txi, doc/interpreter/diagperm.txi, doc/interpreter/diffeq.txi, doc/interpreter/emacs.txi, doc/interpreter/expr.txi, doc/interpreter/external.txi, doc/interpreter/func.txi, doc/interpreter/grammar.txi, doc/interpreter/gui.txi, doc/interpreter/install.txi, doc/interpreter/intro.txi, doc/interpreter/io.txi, doc/interpreter/java.txi, doc/interpreter/linalg.txi, doc/interpreter/matrix.txi, doc/interpreter/nonlin.txi, doc/interpreter/numbers.txi, doc/interpreter/octave.texi, doc/interpreter/optim.txi, doc/interpreter/plot.txi, doc/interpreter/preface.txi, doc/interpreter/quad.txi, doc/interpreter/sparse.txi, doc/interpreter/stats.txi, doc/interpreter/stmt.txi, doc/interpreter/strings.txi, doc/interpreter/system.txi, doc/interpreter/var.txi: Shorten some long subsection names in Manual. Remove excess spaces from ends of @menu definitions.

--- a/doc/interpreter/intro.txi
+++ b/doc/interpreter/intro.txi
@@ -38,9 +38,9 @@
 This document corresponds to Octave version @value{VERSION}.
 
 @menu
-* Running Octave::              
-* Simple Examples::             
-* Conventions::                 
+* Running Octave::
+* Simple Examples::
+* Conventions::
 @end menu
 
 @node Running Octave
@@ -419,11 +419,11 @@
 manual.  You may want to skip this section and refer back to it later.
 
 @menu
-* Fonts::                       
-* Evaluation Notation::         
-* Printing Notation::           
-* Error Messages::              
-* Format of Descriptions::      
+* Fonts::
+* Evaluation Notation::
+* Printing Notation::
+* Error Messages::
+* Format of Descriptions::
 @end menu
 
 @node Fonts
@@ -546,8 +546,8 @@
 The description follows on succeeding lines, sometimes with examples.
 
 @menu
-* A Sample Function Description::  
-* A Sample Command Description::  
+* A Sample Function Description::
+* A Sample Command Description::
 @end menu
 
 @node A Sample Function Description