patch 9.0.0828: various typos

Problem:    Various typos.
Solution:   Correct typos. (closes #11432)
diff --git a/src/term.c b/src/term.c
index 008734c..e4b6587 100644
--- a/src/term.c
+++ b/src/term.c
@@ -155,7 +155,7 @@
 // received.  To avoid redrawing too often, only redraw when t_8u is not reset
 // and it was supposed to be written.  Unless t_8u was set explicitly.
 // FALSE -> don't output t_8u yet
-// MAYBE -> tried outputing t_8u while FALSE
+// MAYBE -> tried outputting t_8u while FALSE
 // OK    -> can write t_8u
 int write_t_8u_state = FALSE;
 # endif