[committed] libstdc++: Fix non-ASCII characters in header

[Jonathan Wakely]

This fixes:
FAIL: 17_intro/headers/c++1998/charset.cc  -std=gnu++26 (test for excess errors)

libstdc++-v3/ChangeLog:

        * include/std/contracts: Replace non-ASCII characters.
---

Tested x86_64-linux. Pushed to trunk.

 libstdc++-v3/include/std/contracts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/include/std/contracts 
b/libstdc++-v3/include/std/contracts
index 2cf67ac1dd88..0fd9b10247ea 100644
--- a/libstdc++-v3/include/std/contracts
+++ b/libstdc++-v3/include/std/contracts
@@ -52,7 +52,7 @@ namespace contracts
     post = 2,
     assert = 3,
 
-    /* Implementation−defined values should have a minimum value of 1000. */
+    /* Implementation-defined values should have a minimum value of 1000. */
   };
 
   enum class evaluation_semantic : __UINT16_TYPE__ {
@@ -61,14 +61,14 @@ namespace contracts
     enforce = 3,
     quick_enforce = 4,
 
-    /* Implementation−defined values should have a minimum value of 1000.  */
+    /* Implementation-defined values should have a minimum value of 1000.  */
   };
 
   enum class detection_mode : __UINT16_TYPE__ {
     predicate_false = 1,
     evaluation_exception = 2,
 
-    /* Implementation−defined values should have a minimum value of 1000. */
+    /* Implementation-defined values should have a minimum value of 1000. */
   };
 
   using __vendor_ext = void;
-- 
2.52.0