[COMMITTED] ada: Fix unescaped quotes when combining fdiagnostics-format=json and gnatdJ

[Marc Poulhiès via Gcc-patches]

From: Ghjuvan Lacambre <lacam...@adacore.com>

This commit fixes a small bug where GNAT would emit unescaped quotes in
its -fdiagnostics-format=json output when using -gnatdJ and emitting
messages about operator functions (e.g. "=").

gcc/ada/

        * errout.adb (Write_JSON_Span): Escape subprogram name.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/errout.adb | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/ada/errout.adb b/gcc/ada/errout.adb
index b30e8b51d15..261ba2e8033 100644
--- a/gcc/ada/errout.adb
+++ b/gcc/ada/errout.adb
@@ -2193,8 +2193,9 @@ package body Errout is
          end if;
 
          if Include_Subprogram_In_Messages then
-            Write_Str
-              (",""subprogram"":""" & Subprogram_Name_Ptr (Error.Node) & """");
+            Write_Str (",""subprogram"":""");
+            Write_JSON_Escaped_String (Subprogram_Name_Ptr (Error.Node));
+            Write_Str ("""");
          end if;
 
          Write_Str ("}");
-- 
2.34.1