Replace single-quoted literals in messaging calls with cli markup

Converted bare 'value' strings inside stop_(), warning_(), message_()
to appropriate cli markup:
- {.val}: option values ('drug', 'dose', 'administration', 'SDD', 'logbook')
- {.cls}: class names ('sir', 'mo')
- {.field}: column names ('mo' in mo_source)
- {.code}: object/dataset names ('clinical_breakpoints')

Files changed: ab_from_text.R, av_from_text.R, sir.R, sir_calc.R, mo_source.R

https://claude.ai/code/session_01XHWLohiSTdZvCutwD7ag2b

R/av_from_text.R

@@ -168,7 +168,7 @@ av_from_text <- function(text,
       }
     })
   } else {
-    stop_("{.arg type} must be either 'drug', 'dose' or 'administration'")
+    stop_("{.arg type} must be either {.val drug}, {.val dose} or {.val administration}")
   }
 
   # collapse text if needed