[Docs] Update section about integrated repl that was removed in Debugging the compiler docs file

Author: LucianoPAlmeida

docs/DebuggingTheCompiler.md

@@ -206,17 +206,12 @@ Conformances:
     (integer_literal_expr type='Int2048' location=test.swift:3:10 range=[test.swift:3:10 - line:3:10] value=0)))
 ```
 
-When using the integrated swift-repl, one can dump the same output for each
+When using swift LLDB REPL, one can dump the same output for each
 expression as one evaluates the expression by enabling constraints debugging by
-typing `:constraints debug on`:
-
-    $ swift -frontend -repl -enable-objc-interop -module-name REPL
-    ***  You are running Swift's integrated REPL,  ***
-    ***  intended for compiler and stdlib          ***
-    ***  development and testing purposes only.    ***
-    ***  The full REPL is built as part of LLDB.   ***
-    ***  Type ':help' for assistance.              ***
-    (swift) :constraints debug on
+passing the flag `-Xfrontend -debug-constraints`:
+
+    $ swift repl -Xfrontend -debug-constraints
+    1> let foo = 1
 
 ## Debugging on SIL Level