update version notes and changelog

doc/pages/changelog.asciidoc

@@ -7,6 +7,9 @@ released versions.
 
 * Re-organized bundled script files directory hierarchy.
 
+* Introduced helpers to write/read from file in scripts with
+  `%file{...}` expansion and `echo -to-file <filename>`.
+
 == Kakoune 2019.01.20
 
 * `auto_complete` has been renamed to `autocomplete` for more

src/main.cc

@@ -44,6 +44,10 @@ struct {
     unsigned int version;
     const char* notes;
 } constexpr version_notes[] = { {
+        0,
+        "» %file{...} expansions to read files\n"
+        "» echo -to-file <filename> to write to file\n"
+    }, {
         20190120,
         "» named capture groups in regex\n"
         "» auto_complete option renamed to autocomplete\n"