patch 8.1.2366: using old C style comments

Problem:    Using old C style comments.
Solution:   Use // comments where appropriate.
diff --git a/src/globals.h b/src/globals.h
index 84fe28b..e96800d 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -853,9 +853,9 @@
 EXTERN pos_T	Insstart;		// This is where the latest
 					// insert/append mode started.
 
-/* This is where the latest insert/append mode started. In contrast to
- * Insstart, this won't be reset by certain keys and is needed for
- * op_insert(), to detect correctly where inserting by the user started. */
+// This is where the latest insert/append mode started. In contrast to
+// Insstart, this won't be reset by certain keys and is needed for
+// op_insert(), to detect correctly where inserting by the user started.
 EXTERN pos_T	Insstart_orig;
 
 /*
@@ -865,7 +865,7 @@
 EXTERN int	vr_lines_changed INIT(= 0); // #Lines changed by "gR" so far
 
 #if defined(FEAT_X11) && defined(FEAT_XCLIPBOARD)
-/* argument to SETJMP() for handling X IO errors */
+// argument to SETJMP() for handling X IO errors
 EXTERN JMP_BUF x_jump_env;
 #endif
 
@@ -1404,7 +1404,7 @@
 #ifdef BACKSLASH_IN_FILENAME
 EXTERN char	psepc INIT(= '\\');	// normal path separator character
 EXTERN char	psepcN INIT(= '/');	// abnormal path separator character
-/* normal path separator string */
+// normal path separator string
 EXTERN char	pseps[2] INIT(= {'\\' COMMA 0});
 #endif