patch 8.2.4907: some users do not want a line comment always inserted

Problem:    Some users do not want a line comment always inserted.
Solution:   Add the '/' flag to 'formatoptions' to not repeat the comment
            leader after a statement when using "o".
diff --git a/src/option.h b/src/option.h
index 936f260..fdbe926 100644
--- a/src/option.h
+++ b/src/option.h
@@ -141,6 +141,7 @@
 #define FO_WRAP_COMS	'c'
 #define FO_RET_COMS	'r'
 #define FO_OPEN_COMS	'o'
+#define FO_NO_OPEN_COMS	'/'
 #define FO_Q_COMS	'q'
 #define FO_Q_NUMBER	'n'
 #define FO_Q_SECOND	'2'
@@ -159,7 +160,7 @@
 
 #define DFLT_FO_VI	"vt"
 #define DFLT_FO_VIM	"tcq"
-#define FO_ALL		"tcroq2vlb1mMBn,aw]jp"	// for do_set()
+#define FO_ALL		"tcro/q2vlb1mMBn,aw]jp"	// for do_set()
 
 // characters for the p_cpo option:
 #define CPO_ALTREAD	'a'	// ":read" sets alternate file name
@@ -196,7 +197,7 @@
 #define CPO_REMMARK	'R'	// remove marks when filtering
 #define CPO_BUFOPT	's'
 #define CPO_BUFOPTGLOB	'S'
-#define CPO_TAGPAT	't'
+#define CPO_TAGPAT	't'	// tag pattern is used for "n"
 #define CPO_UNDO	'u'	// "u" undoes itself
 #define CPO_BACKSPACE	'v'	// "v" keep deleted text
 #define CPO_CW		'w'	// "cw" only changes one blank