tools/gn: Update docs to refer to 'public_configs'.

'direct_dependent_configs' is the deprecated name and should not be used
anymore.

BUG=None
R=dpranke@chromium.org

Review URL: https://codereview.chromium.org/1190393003

Cr-Original-Commit-Position: refs/heads/master@{#335280}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 634ad43fed1e67462429f1e94ec7a4c1c85c0444

tools/gn/docs/quick_start.md

diff --git a/tools/gn/docs/quick_start.md b/tools/gn/docs/quick_start.md
index 49f16ae..10f99ca 100644
--- a/tools/gn/docs/quick_start.md
+++ b/tools/gn/docs/quick_start.md
@@ -248,7 +248,7 @@
 This applies the `hello_config` to the `hello` target itself, plus all
 targets that depend on transitively depend on the current one. Now
 everybody that depends on us will get our settings. You can also set
-`direct_dependent_configs` which applies only to targets that directly
+`public_configs` which applies only to targets that directly
 depend on your target (not transitively).
 
 Now if you compile and run, you'll see the new version with two people: