fix crash, when reading none existing file

IOException catching was not enough. In my case some kind of UnixException was thrown.
Also just softfail when not able read file from disk, do not exit and terminate program.

Author: michaellilltokiwa

src/dev/flang/shared/SourceText.java

@@ -99,9 +99,9 @@ private static String ReadFromDisk(URI uri)
       {
         return Files.readString(Path.of(uri), StandardCharsets.UTF_8);
       }
-    catch (IOException e)
+    catch (Exception e)
       {
-        ErrorHandling.WriteStackTraceAndExit(1, e);
+        ErrorHandling.WriteStackTrace(e);
         return null;
       }
   }

version.txt

@@ -1 +1 @@
-0.89.1
+0.89.2