Update gmock-matchers.h

branch master changed to main on link

Author: assafpr

googlemock/include/gmock/gmock-matchers.h

@@ -240,7 +240,7 @@
 //
 // To learn more about using these macros, please search for 'MATCHER'
 // on
-// https://github.com/google/googletest/blob/master/docs/gmock_cook_book.md
+// https://github.com/google/googletest/blob/main/docs/gmock_cook_book.md
 //
 // This file also implements some commonly used argument matchers.  More
 // matchers can be defined by the user implementing the