Comment wording tweak

Bug: None
Change-Id: I147b1931a064fedceb7e8d97968cda7b98cb686c
Reviewed-on: https://chromium-review.googlesource.com/677425Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Peter Mayo <petermayo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504071}

third_party/WebKit/Source/core/core.gni

@@ -52,7 +52,7 @@ if (is_component_build) {
 # "core". This will either be a source_set (component build), a static library
 # (split_count undefined) or a split static library (split_count defined).
 #
-# Special values. All unlisted values are forwarded to the underlying library.
+# Special values (all unlisted values are forwarded to the underlying library):
 #
 #   configs
 #      Normal meaning. The set_defaults call below will make the default value
@@ -69,7 +69,7 @@ if (is_component_build) {
 #
 #   deps
 #      Normal meaning but "core:prerequisites" target is always added. Callers
-#      shouldn'y list prerequisites as a dependency.
+#      shouldn't list prerequisites as a dependency.
 #
 #   visibility
 #      Normal meaning if defined. If undefined, defaults to everything in core.