patch 8.1.1886: command line expansion code is spread out

Problem:    Command line expansion code is spread out.
Solution:   Move the code to cmdexpand.c. (Yegappan Lakshmanan, closes #4831)
diff --git a/Filelist b/Filelist
index 464d730..af06f0c 100644
--- a/Filelist
+++ b/Filelist
@@ -24,6 +24,7 @@
 		src/change.c \
 		src/channel.c \
 		src/charset.c \
+		src/cmdexpand.c \
 		src/cmdhist.c \
 		src/crypt.c \
 		src/crypt_zip.c \
@@ -175,6 +176,7 @@
 		src/proto/change.pro \
 		src/proto/channel.pro \
 		src/proto/charset.pro \
+		src/proto/cmdexpand.pro \
 		src/proto/cmdhist.pro \
 		src/proto/crypt.pro \
 		src/proto/crypt_zip.pro \