Fix various spelling errors (#2293)

* Fix spelling errors in log messages

* Fix doc comment syntax

* Fix spelling errors in Markdown documentation

* Fix spelling errors in comments

custom_mutators/libfuzzer/FuzzerTracePC.cpp

@@ -460,7 +460,7 @@ static size_t InternalStrnlen(const char *S, size_t MaxLen) {
 }
 
 // Finds min of (strlen(S1), strlen(S2)).
-// Needed bacause one of these strings may actually be non-zero terminated.
+// Needed because one of these strings may actually be non-zero terminated.
 static size_t InternalStrnlen2(const char *S1, const char *S2) {
 
   size_t Len = 0;