help: move revsets.## documentation into infix section

mercurial/help/revsets.txt

@@ -55,6 +55,22 b' These are the supported infix operators:'
 ``x~n``
   The nth first ancestor of x; ``x~0`` is x; ``x~3`` is ``x^^^``.
 
+``x ## y``
+  Concatenate strings and identifiers into one string.
+
+  All other prefix, infix and postfix operators have lower priority than
+  ``##``. For example, ``a1 ## a2~2`` is equivalent to ``(a1 ## a2)~2``.
+
+  For example::
+
+    [revsetalias]
+    issue(a1) = grep(r'\bissue[ :]?' ## a1 ## r'\b|\bbug\(' ## a1 ## r'\)')
+
+    ``issue(1234)`` is equivalent to
+    ``grep(r'\bissue[ :]?1234\b|\bbug\(1234\)')``
+    in this case. This matches against all of "issue 1234", "issue:1234",
+    "issue1234" and "bug(1234)".
+
 There is a single postfix operator:
 
 ``x^``
@@ -86,18 +102,6 b' For example,'
 defines three aliases, ``h``, ``d``, and ``rs``. ``rs(0:tip, author)`` is
 exactly equivalent to ``reverse(sort(0:tip, author))``.
 
-An infix operator ``##`` can concatenate strings and identifiers into
-one string. For example::
-
-  [revsetalias]
-  issue(a1) = grep(r'\bissue[ :]?' ## a1 ## r'\b|\bbug\(' ## a1 ## r'\)')
-
-``issue(1234)`` is equivalent to ``grep(r'\bissue[ :]?1234\b|\bbug\(1234\)')``
-in this case. This matches against all of "issue 1234", "issue:1234",
-"issue1234" and "bug(1234)".
-
-All other prefix, infix and postfix operators have lower priority than
-``##``. For example, ``a1 ## a2~2`` is equivalent to ``(a1 ## a2)~2``.
 
 Command line equivalents for :hg:`log`::