patch 9.0.1425: "wat" and "wast" files are one filetype

Problem:    "wat" and "wast" files are one filetype.
Solution:   Add a separate filetype for "wat" files. (Amaan Qureshi,
            closes #12165)
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 8b42250..2ae36b3 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -657,7 +657,8 @@
     \ 'vrml': ['file.wrl'],
     \ 'vroom': ['file.vroom'],
     \ 'vue': ['file.vue'],
-    \ 'wast': ['file.wast', 'file.wat'],
+    \ 'wat': ['file.wat'],
+    \ 'wast': ['file.wast'],
     \ 'wdl': ['file.wdl'],
     \ 'webmacro': ['file.wm'],
     \ 'wget': ['.wgetrc', 'wgetrc'],
diff --git a/src/version.c b/src/version.c
index 2438733..63428d3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1425,
+/**/
     1424,
 /**/
     1423,