Revert "Add an explanation to ndk_library."

This reverts commit ba9f9262a3.

Reason for revert: DroidMonitor created revert due to b/364440900.

Change-Id: I8661cdce1a1187459b6a0acde4c64a5aa70dcc87

cc/ndk_library.go

@@ -103,17 +103,8 @@ type libraryProperties struct {
 	// https://github.com/android-ndk/ndk/issues/265.
 	Unversioned_until *string
 
-	// DO NOT USE THIS
-	// NDK libraries should not export their headers. Headers belonging to NDK
-	// libraries should be added to the NDK with an ndk_headers module.
+	// Headers presented by this library to the Public API Surface
 	Export_header_libs []string
-
-	// Do not add other export_* properties without consulting with danalbert@.
-	// Consumers of ndk_library modules should emulate the typical NDK build
-	// behavior as closely as possible (that is, all NDK APIs are exposed to
-	// builds via --sysroot). Export behaviors used in Soong will not be present
-	// for app developers as they don't use Soong, and reliance on these export
-	// behaviors can mask issues with the NDK sysroot.
 }
 
 type stubDecorator struct {