Update runtime files.
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index ed4f8aa..d8994ef 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1,4 +1,4 @@
-*eval.txt* For Vim version 8.2. Last change: 2020 Jul 19
+*eval.txt* For Vim version 8.2. Last change: 2020 Jul 21
VIM REFERENCE MANUAL by Bram Moolenaar
@@ -1994,6 +1994,8 @@
*v:none* *none-variable* *None*
v:none An empty String. Used to put an empty item in JSON. See
|json_encode()|.
+ This can also be used as a function argument to use the
+ default value, see |none-function_argument|.
When used as a number this evaluates to zero.
When used as a string this evaluates to "v:none". >
echo v:none
@@ -11710,7 +11712,7 @@
call, not definition. Thus it is possible to use an expression which is
invalid the moment the function is defined. The expressions are also only
evaluated when arguments are not specified during a call.
-
+ *none-function_argument*
You can pass |v:none| to use the default expression. Note that this means you
cannot pass v:none as an ordinary value when an argument has a default
expression.