Fix block descriptor documentation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115362 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/SourceLevelDebugging.html b/docs/SourceLevelDebugging.html
index 4e65bf4..ca7dd72 100644
--- a/docs/SourceLevelDebugging.html
+++ b/docs/SourceLevelDebugging.html
@@ -461,14 +461,16 @@
 <pre>
 !3 = metadata !{
   i32,     ;; Tag = 13 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
-  metadata ;; Reference to context descriptor
+  metadata,;; Reference to context descriptor
+  i32,     ;; Line number
+  i32      ;; Column number
 }
 </pre>
 </div>
 
 <p>These descriptors provide debug information about nested blocks within a
-   subprogram.  The array of member descriptors is used to define local
-   variables and deeper nested blocks.</p>
+   subprogram. The line number and column numbers are used to dinstinguish
+   two lexical blocks at same depth. </p>
 
 </div>