vim: Fix some dw edge cases (#3058)

Release Notes:

- vim: Fix `dw` on the last word of a line, and on empty lines.

crates/vim/test_data/test_command_replace.json

@@ -20,10 +20,3 @@
 {"Key":"0"}
 {"Key":"enter"}
 {"Get":{"state":"aa\ndd\nˇcc","mode":"Normal"}}
-{"Key":":"}
-{"Key":"%"}
-{"Key":"s"}
-{"Key":"/"}
-{"Key":"/"}
-{"Key":"/"}
-{"Key":"enter"}

crates/vim/test_data/test_delete_w.json

@@ -1,3 +1,7 @@
+{"Put":{"state":"Test tesˇt\n    test"}}
+{"Key":"d"}
+{"Key":"w"}
+{"Get":{"state":"Test teˇs\n    test","mode":"Normal"}}
 {"Put":{"state":"Teˇst"}}
 {"Key":"d"}
 {"Key":"w"}
@@ -14,6 +18,10 @@
 {"Key":"d"}
 {"Key":"w"}
 {"Get":{"state":"Test teˇs\ntest","mode":"Normal"}}
+{"Put":{"state":"Test test\nˇ\ntest"}}
+{"Key":"d"}
+{"Key":"w"}
+{"Get":{"state":"Test test\nˇtest","mode":"Normal"}}
 {"Put":{"state":"Test teˇst-test test"}}
 {"Key":"d"}
 {"Key":"shift-w"}