[doc/ysh-tour] Mention advanced features, ARGV, ENV

- Improve CSS

Still TODO:

- Improve section on Data Notation
- Probably move "Advanced Features" to the appendix

build/doc.sh

@@ -447,14 +447,58 @@ tour() {
 
   # Files used by module example
   touch $work_dir/{build,test}.sh
+
+  cat >$work_dir/myargs.ysh <<EOF
+const __provide__ = :| proc1 p2 p3 |
+
+proc proc1 {
+  echo proc1
+}
+
+proc p2 {
+  echo p2
+}
+
+proc p3 {
+  echo p3
+}
+EOF
+
+  cat >$work_dir/demo.py <<EOF
+#!/usr/bin/env python3
+
+print("hi")
+EOF
+  chmod +x $work_dir/demo.py
 
   cat >$work_dir/lib/util.ysh <<EOF
-log() { echo "$@" 1>&2; }
+const __provide__ = :| log |
+
+proc log {
+  echo @ARGV >&2
+}
 EOF
 
   pushd $work_dir
+
+  # Prepend extra code
+  cat >tour.ysh - $name.txt <<EOF
+func myMethod(self) {
+  echo 'myMethod'
+}
+
+func mutatingMethod(self) {
+  echo 'mutatingMethod'
+}
+
+func makeMyObject(x) {
+  var methods = Object(null, {myMethod, 'M/mutatingMethod': mutatingMethod})
+  return (Object(methods, {x}))
+}
+EOF
+
   # Fix: don't supply stdin!
-  $REPO_ROOT/bin/ysh $name.txt < /dev/null
+  $REPO_ROOT/bin/ysh tour.ysh < /dev/null
   popd
 
   # My own dev tools

doc/upgrade-breakage.md

@@ -184,6 +184,8 @@ Shells](known-differences.html).
 
 ## Appendix
 
+Here are some notable **non-breaking** changes.
+
 ### Shell Functions vs. Procs
 
 Procs have truly local variables like Python and JavaScript.  There's no
@@ -192,6 +194,16 @@ Procs have truly local variables like Python and JavaScript.  There's no
 This is something to be aware of, but isn't technically a breakage because
 shell functions still work the same way in YSH.
 
+### $EDITOR vs. ENV.EDITOR 
+
+In YSH, env vars live in the [ENV][] dict.  So instead of `$EDITOR`, you should
+use `$[ENV.EDITOR]`.
+
+But doesn't break when you `shopt --set ysh:upgrade`, only when you use
+`bin/ysh`.
+
+[ENV]: ref/chap-special-var.html#ENV
+
 ### Acknowledgments
 
 Thank you to `ca2013` for reviewing this doc.