Several details about 5.4.0 rc1

Corrected several small details: added 'const', adjusts in tabs x
spaces, removed unused #includes and #defines, misspellings, etc.

lobject.h

@@ -356,8 +356,7 @@ typedef struct GCObject {
 
 
 /*
-** Header for string value; string bytes follow the end of this structure
-** (aligned according to 'UTString'; see next).
+** Header for string value; string bytes follow the end of this structure.
 */
 typedef struct TString {
   CommonHeader;