[mlir] Tidy double the in comment

[seanshpark]

Summary

This will tidy double 'the' in the comment for 'getInsertionBlock()'.

[seanshpark]

Hope some could land this change :)

[jpienaar]

Will help land.

mlir/include/mlir/IR/Builders.h

public:
   }
 
   /// Sets the insertion point to the end of the specified block.
   void setInsertionPointToEnd(Block *block) {
     setInsertionPoint(block, block->end());
   }
 
   /// Return the block the current insertion point belongs to.  Note that the
-  /// the insertion point is not necessarily the end of the block.
+  /// insertion point is not necessarily the end of the block.
   Block *getInsertionBlock() const { return block; }
 
   /// Returns the current insertion point of the builder.
   Block::iterator getInsertionPoint() const { return insertPoint; }
 
   /// Returns the current block of the builder.
   Block *getBlock() const { return block; }