glsl: Fix Doxygen tag \file in recently renamed files
diff --git a/src/glsl/opt_dead_code.cpp b/src/glsl/opt_dead_code.cpp
index 5cf5e99..cb500d2 100644
--- a/src/glsl/opt_dead_code.cpp
+++ b/src/glsl/opt_dead_code.cpp
@@ -22,7 +22,7 @@
  */
 
 /**
- * \file ir_dead_code.cpp
+ * \file opt_dead_code.cpp
  *
  * Eliminates dead assignments and variable declarations from the code.
  */