patch 8.0.0783: job of terminal may be freed too early

Problem:    Job of terminal may be freed too early.
Solution:   Increment job refcount. (Yasuhiro Matsumoto)
diff --git a/src/terminal.c b/src/terminal.c
index 6f14b3f..6d8679d 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -1247,6 +1247,7 @@
     job->jv_proc_info.dwProcessId = GetProcessId(child_process_handle);
     job->jv_job_object = jo;
     job->jv_status = JOB_STARTED;
+    ++job->jv_refcount;
     term->tl_job = job;
 
     return OK;
@@ -1329,6 +1330,8 @@
     argvars[0].vval.v_string = cmd;
     setup_job_options(&opt, rows, cols);
     term->tl_job = job_start(argvars, &opt);
+    if (term->tl_job != NULL)
+	++term->tl_job->jv_refcount;
 
     return term->tl_job != NULL
 	&& term->tl_job->jv_channel != NULL
diff --git a/src/version.c b/src/version.c
index da00188..1b13fd3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -770,6 +770,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    783,
+/**/
     782,
 /**/
     781,