Make sure string literals contain line breaks

Fix the lexer to include the newlines.

Signed-off-by: Stefan Marr <git@stefan-marr.de>

core-lib/TestSuite/StringTests.som

@@ -131,6 +131,14 @@ class StringTests usingPlatform: platform testFramework: minitest = (
 1234567890
 1234567890'
     )
+
+    public testMultLineStringPreserveNewlines = (
+      | str |
+      str := '123
+567'.
+      assert: '\n' equals: (str charAt: 4).
+      assert: 7 equals: str length.
+    )
 
     public testEscapeSequences = (
       (* Tests for escape sequences, not all of them are reliable represented

src/som/compiler/Lexer.java

@@ -293,6 +293,7 @@ private void lexString() {
         if (fillBuffer() == -1) {
           return;
         }
+        state.text.append('\n');
       }
     }