patch 8.2.0464: typos and other small problems

Problem:    Typos and other small problems.
Solution:   Fix the typos.  Add missing files to the distribution.
diff --git a/Filelist b/Filelist
index 2ea9a6f..25bfb4c 100644
--- a/Filelist
+++ b/Filelist
@@ -12,6 +12,7 @@
 		appveyor.yml \
 		ci/appveyor.bat \
 		ci/if_ver*.vim \
+		ci/load-snd-dummy.sh \
 		src/Make_all.mak \
 		src/README.md \
 		src/alloc.h \
@@ -151,17 +152,18 @@
 		src/testdir/*.py \
 		src/testdir/lsan-suppress.txt \
 		src/testdir/sautest/autoload/*.vim \
-		src/testdir/runtest.vim \
-		src/testdir/summarize.vim \
 		src/testdir/check.vim \
-		src/testdir/shared.vim \
-		src/testdir/screendump.vim \
-		src/testdir/view_util.vim \
-		src/testdir/term_util.vim \
-		src/testdir/setup.vim \
 		src/testdir/gui_init.vim \
-		src/testdir/setup_gui.vim \
 		src/testdir/gui_preinit.vim \
+		src/testdir/mouse.vim \
+		src/testdir/runtest.vim \
+		src/testdir/screendump.vim \
+		src/testdir/setup.vim \
+		src/testdir/setup_gui.vim \
+		src/testdir/shared.vim \
+		src/testdir/summarize.vim \
+		src/testdir/term_util.vim \
+		src/testdir/view_util.vim \
 		src/testdir/test[0-9]*.ok \
 		src/testdir/test[0-9]*a.ok \
 		src/testdir/test_[a-z]*.ok \