Document warn_deprecated_catch option

Author: richcarl

lib/compiler/src/compile.erl

@@ -656,6 +656,12 @@ value are listed.
   Default is to emit warnings for every use of a callback known by the compiler to
   be deprecated.
 
+- **`warn_deprecated_catch`** - Enables warnings for use of old style catch
+  expressions on the form `catch Expr` instead of the modern `try ... catch
+  ... end`. You may enable this compiler option on the project level and
+  add `-compile(nowarn_deprecated_catch).` to individual files which still
+  contain old catches in order to prevent new uses from getting added.
+
 - **`nowarn_removed`** - Turns off warnings for calls to functions that have
   been removed. Default is to emit warnings for every call to a function known
   by the compiler to have been recently removed from Erlang/OTP.