vim-patch:8.1.1526: no numerical value for the patchlevel

Problem:    No numerical value for the patchlevel.
Solution:   Add v:versionlong.

37df9a4401

Restore "highest_patch()" solely for "v:versionlong".
Copy/paste Test_vvar_scriptversion2() from patch 9.1.1540.
It works without ":scriptversion 2".
In general, if Vim's test works with ":scriptversion 1", just port it
for additional coverage.

---

vim-patch:8.1.1565: MS-Windows: no sound support

Problem:    MS-Windows: no sound support.
Solution:   Add sound support for MS-Windows. (Yasuhiro Matsumoto, Ken Takata,
            closes vim/vim#4522)

9b283523f2

----

"sound" feature is N/A now but this updates "v:versionlong" docs.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/vvars.lua

@@ -878,6 +878,21 @@ M.vars = {
       <
     ]=],
   },
+  versionlong = {
+    type = 'integer',
+    desc = [=[
+      Like v:version, but also including the patchlevel in the last
+      four digits.  Version 8.1 with patch 123 has value 8010123.
+      This can be used like this: >
+        if v:versionlong >= 8010123
+      <
+      However, if there are gaps in the list of patches included
+      this will not work well.  This can happen if a recent patch
+      was included into an older version, e.g. for a security fix.
+      Use the has() function to make sure the patch is actually
+      included.
+    ]=],
+  },
   vim_did_enter = {
     type = 'integer',
     desc = [=[