editor: save and reset terminal after calling EDITOR

When EDITOR is invoked to modify a commit message, it will likely
change the terminal settings, and if it misbehaves will leave the
terminal output damaged as shown in a recent report from Windows
Terminal[1]

Instead use the functions provided by compat/terminal to save the
settings and recover safely.

[1] microsoft/terminal#9359

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>

editor.c

@@ -3,6 +3,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 #include "sigchain.h"
+#include "compat/terminal.h"
 
 #ifndef DEFAULT_EDITOR
 #define DEFAULT_EDITOR "vi"
@@ -50,6 +51,8 @@ const char *git_sequence_editor(void)
 static int launch_specified_editor(const char *editor, const char *path,
 				   struct strbuf *buffer, const char *const *env)
 {
+	int term_fail;
+
 	if (!editor)
 		return error("Terminal is dumb, but EDITOR unset");
 
@@ -83,14 +86,19 @@ static int launch_specified_editor(const char *editor, const char *path,
 		p.env = env;
 		p.use_shell = 1;
 		p.trace2_child_class = "editor";
+		term_fail = save_term(1);
 		if (start_command(&p) < 0) {
+			if (!term_fail)
+				restore_term();
 			strbuf_release(&realpath);
 			return error("unable to start editor '%s'", editor);
 		}
 
 		sigchain_push(SIGINT, SIG_IGN);
 		sigchain_push(SIGQUIT, SIG_IGN);
 		ret = finish_command(&p);
+		if (!term_fail)
+			restore_term();
 		strbuf_release(&realpath);
 		sig = ret - 128;
 		sigchain_pop(SIGINT);