Use a consistent plural for 'corpus'.

'corpora' seems to be more common than 'corpuses' in Chromium code
search, including in libFuzzer's source itself.

Change-Id: I6489b57a4608f47274c4400aac135cbfb991953a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46825
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

FUZZING.md

@@ -42,11 +42,11 @@ These were determined by rounding up the length of the largest case in the corpu
 
 There are directories in `fuzz/` for each of the fuzzing tests which contain seed files for fuzzing. Some of the seed files were generated manually but many of them are “interesting” results generated by the fuzzing itself. (Where “interesting” means that it triggered a previously unknown path in the code.)
 
-## Minimising the corpuses
+## Minimising the corpora
 
 When a large number of new seeds are available, it's a good idea to minimise the corpus so that different seeds that trigger the same code paths can be deduplicated.
 
-In order to minimise all the corpuses, build for fuzzing and run `./fuzz/minimise_corpuses.sh`. Note that minimisation is, oddly, often not idempotent for unknown reasons.
+In order to minimise all the corpora, build for fuzzing and run `./fuzz/minimise_corpora.sh`. Note that minimisation is, oddly, often not idempotent for unknown reasons.
 
 ## Fuzzer mode