patch 8.2.1898: command modifier parsing always uses global cmdmod

Problem:    Command modifier parsing always uses global cmdmod.
Solution:   Pass in cmdmod_T to use.  Rename struct fields consistently.
diff --git a/src/session.c b/src/session.c
index e1bb300..829cca9 100644
--- a/src/session.c
+++ b/src/session.c
@@ -1144,7 +1144,7 @@
 	fname = (char_u *)EXRC_FILE;
 
 #ifdef FEAT_BROWSE
-    if (cmdmod.browse)
+    if (cmdmod.cmod_flags & CMOD_BROWSE)
     {
 	browseFile = do_browse(BROWSE_SAVE,
 # ifdef FEAT_SESSION