"master" was renamed "main".

Test: N/A
Change-Id: I86d5578eaac260e55a9583db7ab49812b4ba1f5d
diff --git a/cc/ndk_headers.go b/cc/ndk_headers.go
index 0fbc8d0..567cb7c 100644
--- a/cc/ndk_headers.go
+++ b/cc/ndk_headers.go
@@ -182,7 +182,7 @@
 }
 
 // Like ndk_headers, but preprocesses the headers with the bionic versioner:
-// https://android.googlesource.com/platform/bionic/+/master/tools/versioner/README.md.
+// https://android.googlesource.com/platform/bionic/+/main/tools/versioner/README.md.
 //
 // Unlike ndk_headers, we don't operate on a list of sources but rather a whole directory, the
 // module does not have the srcs property, and operates on a full directory (the `from` property).
@@ -267,7 +267,7 @@
 }
 
 // versioned_ndk_headers preprocesses the headers with the bionic versioner:
-// https://android.googlesource.com/platform/bionic/+/master/tools/versioner/README.md.
+// https://android.googlesource.com/platform/bionic/+/main/tools/versioner/README.md.
 // Unlike the ndk_headers soong module, versioned_ndk_headers operates on a
 // directory level specified in `from` property. This is only used to process
 // the bionic/libc/include directory.