bugfix: invalid indentation for 'else' is detected; optional indentation for 'if' expressions

tests/reject/tind1.nim

@@ -0,0 +1,27 @@
+discard """
+  line: 24
+  errormsg: "invalid indentation"
+"""
+
+import macros
+
+# finally optional indentation in 'if' expressions :-):
+var x = if 4 != 5:
+    "yes"
+  else:
+    "no"
+
+macro mymacro(n: expr): expr = result = n[1][0]
+
+mymacro:
+  echo "test"
+else:
+  echo "else part"
+  
+
+if 4 == 3:
+  echo "bug"
+  else:
+  echo "no bug"
+
+