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/version.c

@@ -2528,6 +2528,12 @@ bool has_nvim_version(const char *const version_str)
                       && patch <= NVIM_VERSION_PATCH))));
 }
 
+int highest_patch(void)
+{
+  // this relies on the highest patch number to be the first entry
+  return included_patches[0];
+}
+
 /// Checks whether a Vim patch has been included.
 ///
 /// @param n Patch number.