Improve paranoid_checks API comment (#13206)

Summary:
see comment change

Pull Request resolved: #13206

Test Plan: no functional change

Reviewed By: cbi42

Differential Revision: D67108123

Pulled By: pdillinger

fbshipit-source-id: 669de1fff8df452c3e279f311452f02b40a03aaf

include/rocksdb/options.h

@@ -571,11 +571,19 @@ struct DBOptions {
   // Default: false
   bool error_if_exists = false;
 
-  // If true, RocksDB will aggressively check consistency of the data.
-  // Also, if any of the  writes to the database fails (Put, Delete, Merge,
-  // Write), the database will switch to read-only mode and fail all other
-  // Write operations.
-  // In most cases you want this to be set to true.
+  // If true, RocksDB does some pro-active and generally inexpensive checks
+  // for DB or data corruption, on top of usual protections such as block
+  // checksums. True also enters a read-only mode when a DB write fails;
+  // see DB::Resume().
+  //
+  // As most workloads value data correctness over availability, this option
+  // is on by default. Note that the name of this old option is potentially
+  // misleading, and other options and operations go further in proactive
+  // checking for corruption, including
+  // * paranoid_file_checks
+  // * paranoid_memory_checks
+  // * DB::VerifyChecksum()
+  //
   // Default: true
   bool paranoid_checks = true;