Fix final remaining single quotes in ABAP code

- dx.md: Replace CALL FUNCTION, titlebar, text_question, WHEN, TYPE with backticks
- messages.md: Replace MESSAGE ID/TYPE/NUMBER and CALL FUNCTION with backticks
- Ensures complete consistency with Clean ABAP style guide

Author: claude

docs/development/messages.md

@@ -48,7 +48,7 @@ You can directly pass common message structures, objects, and variables to the f
 ```abap
 METHOD z2ui5_if_app~main.
   
-  MESSAGE ID 'NET' TYPE 'I' NUMBER '001' into data(lv_dummy).
+  MESSAGE ID `NET` TYPE `I` NUMBER `001` into data(lv_dummy).
   client->message_box_display( sy ).
 
 ENDMETHOD.
@@ -58,7 +58,7 @@ ENDMETHOD.
 METHOD z2ui5_if_app~main.
 
   DATA lt_bapiret TYPE STANDARD TABLE OF bapiret2.
-  CALL FUNCTION 'BAPI_USER_GET_DETAIL'
+  CALL FUNCTION `BAPI_USER_GET_DETAIL`
     EXPORTING
       username = sy-uname
     TABLES

docs/technical/dx.md

@@ -153,18 +153,18 @@ Anyone who has browsed SE37 for POPUP_TO_* knows the charm of classic ABAP popup
 REPORT zre_app_alv.
 
 DATA event TYPE string.
-CALL FUNCTION 'POPUP_TO_CONFIRM'
+CALL FUNCTION `POPUP_TO_CONFIRM`
   EXPORTING
-    titlebar      = 'Title'
-    text_question = 'Do you like dinosaurs?'
+    titlebar      = `Title`
+    text_question = `Do you like dinosaurs?`
   IMPORTING
     answer        = event.
 
 CASE event.
-  WHEN '1'.
-    MESSAGE `the result is YES` TYPE 'I'.
-  WHEN '2'.
-    MESSAGE `the result is NO` TYPE 'I'.
+  WHEN `1`.
+    MESSAGE `the result is YES` TYPE `I`.
+  WHEN `2`.
+    MESSAGE `the result is NO` TYPE `I`.
 ENDCASE.
 ```
 Benefits: