[Ada] Improve bug box customer language

[Pierre-Marie de Rodat]

The language used in the bugbox for a customer to report an error
message is missing an upper-case for the start of a sentence and also
could be worded a bit clearer.

Tested on x86_64-pc-linux-gnu, committed on trunk

2020-06-16  Richard Kenner  <ken...@adacore.com>

gcc/ada/

        * comperr.adb (Compiler_Abort): Clarify message displayed to
        customers.
--- gcc/ada/comperr.adb
+++ gcc/ada/comperr.adb
@@ -330,12 +330,12 @@ package body Comperr is
                   End_Line;
 
                   Write_Str
-                    ("| alternatively submit a bug report by email " &
-                     "to rep...@adacore.com,");
+                    ("| Or submit a bug report by email " &
+                     "to rep...@adacore.com");
                   End_Line;
 
                   Write_Str
-                    ("| including your customer number #nnn " &
+                    ("| and include your customer number #nnn " &
                      "in the subject line.");
                   End_Line;
                end if;