Fix a typo in the doc of "generated_file"

Change-Id: Id16d8673a1e074bc4de07f3c621bab36fa21ad18
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/12060
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>

src/gn/functions_target.cc

diff --git a/src/gn/functions_target.cc b/src/gn/functions_target.cc
index 4e8038f..7120b3f 100644
--- a/src/gn/functions_target.cc
+++ b/src/gn/functions_target.cc
@@ -888,10 +888,10 @@
   The `output_conversion` variable specified the format to write the
   value. See `gn help io_conversion`.
 
-  One of `contents` or `data_keys` must be specified; use of `data` will write
-  the contents of that value to file, while use of `data_keys` will trigger a
-  metadata collection walk based on the dependencies of the target and the
-  optional values of the `rebase` and `walk_keys` variables. See
+  One of `contents` or `data_keys` must be specified; use of `contents` will
+  write the contents of that value to file, while use of `data_keys` will
+  trigger a metadata collection walk based on the dependencies of the target and
+  the optional values of the `rebase` and `walk_keys` variables. See
   `gn help metadata`.
 
   Collected metadata, if specified, will be returned in postorder of