[libfuzzer] improve introductory sentence

This merely adds a missing "an" in the introductory sentence.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D121760

diff --git a/llvm/docs/LibFuzzer.rst b/llvm/docs/LibFuzzer.rst
index 0341e8e..d437460 100644 (file)
--- a/llvm/docs/LibFuzzer.rst
+++ b/llvm/docs/LibFuzzer.rst
@@ -8,7 +8,7 @@ libFuzzer – a library for coverage-guided fuzz testing.
 Introduction
 ============
 
-LibFuzzer is in-process, coverage-guided, evolutionary fuzzing engine.
+LibFuzzer is an in-process, coverage-guided, evolutionary fuzzing engine.
 
 LibFuzzer is linked with the library under test, and feeds fuzzed inputs to the
 library via a specific fuzzing entrypoint (aka "target function"); the fuzzer