[master] 7bebe5888 improve operator documentation

[Nils Goroll]

commit 7bebe588852a511f428f857331ec1e0959115801
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Mar 5 21:51:52 2020 +0100

    improve operator documentation

diff --git a/doc/sphinx/reference/vcl.rst b/doc/sphinx/reference/vcl.rst
index ffd22bae9..0f9fe4a93 100644
--- a/doc/sphinx/reference/vcl.rst
+++ b/doc/sphinx/reference/vcl.rst
@@ -40,20 +40,25 @@ The following operators are available in VCL:
   ``=``
     Assignment operator.
 
-  ``==``
-    Comparison.
+  ``+=``, ``-=``, ``*=``, ``/=``
+    Assign and increment/decrement/multiply/divide operator.
 
-  ``~``
-    Match. Can either be used with regular expressions or ACLs.
+    For strings, ``+=`` appends.
+
+  ``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=``
+    Comparisons
+
+  ``~``, ``!~``
+    Match / non-match. Can either be used with regular expressions or ACLs.
 
   ``!``
     Negation.
 
-  ``&&``
-    Logical and.
+  ``&&`` / ``||``
+    Logical and/or.
 
-  ``||``
-    Logical or.
+  ``<<``, ``>>``
+    left/right bit-shift
 
 
 Conditionals