Tag gdb properly

Author: rocky

docs/commands/data/display.rst

@@ -12,7 +12,7 @@ char, `/x` for hex, `/o` for octal, `/f` for float or `/s` for string.
 
 For now, display expressions are only evaluated when in the same
 code as the frame that was in effect when the display expression
-was set.  This is a departure from gdb and we may allow for more
+was set.  This is a departure from *gdb*, and we may allow for more
 flexibility in the future to specify whether this should be the
 case or not.