docs: simplify toctree of release notes

The existing globbing had too many overly-specific cases.

This led to quite a few documents having globs that matched nothing,
like:

    x/?.?.??

Unless there was a 3.5.10, this would match nothing.  Given how we
structure these documents, `x/*` is enough.  I've left the `x/*-alpha`
type patterns in place, just to keep the ordering a little nicer, for
now.

docsrc/imap/download/release-notes/3.0/index.rst

@@ -8,7 +8,6 @@ Cyrus IMAP 3.0 Releases
     :maxdepth: 1
     :glob:
 
-    x/?.?.*-beta*
-    x/?.?.*-rc*
-    x/?.?.?
-    x/?.?.??
+    x/*-beta*
+    x/*-rc*
+    x/*

docsrc/imap/download/release-notes/3.1/index.rst

@@ -15,4 +15,4 @@ Cyrus IMAP 3.1 Tags
     :maxdepth: 1
     :glob:
 
-    x/?.?.*
+    x/*

docsrc/imap/download/release-notes/3.2/index.rst

@@ -8,7 +8,6 @@ Cyrus IMAP 3.2 Releases
     :maxdepth: 1
     :glob:
 
-    x/?.?.*-beta*
-    x/?.?.*-rc*
-    x/?.?.?
-    x/?.?.??
+    x/*-beta*
+    x/*-rc*
+    x/*

docsrc/imap/download/release-notes/3.3/index.rst

@@ -15,5 +15,4 @@ Cyrus IMAP 3.3 Tags
     :maxdepth: 1
     :glob:
 
-    x/?.?.?
-    x/?.?.??
+    x/*

docsrc/imap/download/release-notes/3.4/index.rst

@@ -8,8 +8,6 @@ Cyrus IMAP 3.4 Releases
     :maxdepth: 1
     :glob:
 
-    x/?.?.*-alpha*
-    x/?.?.*-beta*
-    x/?.?.*-rc*
-    x/?.?.?
-    x/?.?.??
+    x/*-beta*
+    x/*-rc*
+    x/*

docsrc/imap/download/release-notes/3.5/index.rst

@@ -12,9 +12,3 @@ Cyrus IMAP 3.5 Tags
     there will generally be **large breaking changes** occurring between
     releases in this series.
 
-.. toctree::
-    :maxdepth: 1
-    :glob:
-
-    x/?.?.?
-    x/?.?.??