FEAT: WRITE action if used on FILE is returning the same file name in…

…stead of (closed) port!

It enables chaining actions... for example:
```
>> query write %xxx "a"
== make object! [
    name: %/X/GIT/Rebol/release-x64/xxx
    size: 1
    date: 19-Dec-2018/0:17:51.338+1:00
    type: 'file
]
```

Related to: metaeducation/rebol-issues#2337

Note: `save` function is now also returning file!

src/core/p-file.c

@@ -482,6 +482,7 @@ REBINT Mode_Syms[] = {
  }
 
  if (file->error) Trap1(RE_WRITE_ERROR, path);
+ *D_RET = *path;
  break;
 
  case A_OPEN:

src/tests/units/compress-test.r3

@@ -74,7 +74,7 @@ data: "test test test"
  --test-- "GZIP codec"
  --assert binary? alice: load %units/files/alice29.txt.gz
  --assert #{37A087D23C8709E97AA45ECE662FAF3D07006A58} = checksum/method alice 'sha1
- --assert port? save %units/files/tmp.gz alice
+ --assert file? save %units/files/tmp.gz alice
  --assert binary? alice: load %units/files/tmp.gz
  --assert #{37A087D23C8709E97AA45ECE662FAF3D07006A58} = checksum/method alice 'sha1
  delete %units/files/tmp.gz

src/tests/units/port-test.r3

@@ -51,6 +51,12 @@ Rebol [
  --assert ["a" ""] = read/lines %tmp.txt
  delete %tmp.txt
 
+ --test-- "write file result - wish/2337"
+ ;@@ https://github.com/rebol/rebol-issues/issues/2337
+ --assert file? write %foo "hello"
+ --assert "hello" = read/string write %foo "hello"
+ delete %foo
+
 ===end-group===
 
 if "true" <> get-env "CONTINUOUS_INTEGRATION" [