Improvements and bugfixes to the depot_tools doc generation process.

docs/src/depot_tools_tutorial.demo.tldr.sh

 #!/bin/bash
 BLANK_DEMO=1
 . demo_repo.sh
 
 trunc() {
   echo ... truncated output ...
 }
 
 trunc_command() {
   pcommand "$@"
   trunc
 }
 
 WS=build/whitespace_file.txt
 add_ws() {
   praw cat '>>' $WS '<<EOF'
   echo -e "$1"
   echo EOF
   echo -e "$1" >> $WS
 }
 
 ed_ws() {
   echo -ne "\x1B[37;1m$ echo -e "
   echo -n "'$1'"
   echo -e " | ed $WS\x1B[m"
-  echo -e "$1" | ed $WS
+  echo -e "$1" | ed $WS 2>&1
 }
 
 # needs an extra echo afterwards
 map() {
   run git map
   echo
 }
 
 ED1='/Banana\ns/Banana/Kuun\nwq'
 
@@ skipping 73 matching lines @@
 comment "Since we know that chapter 3 depends on chapter 2, we'll track the"
 comment "current chapter2 branch."
 run git new-branch --upstream_current chap3
 add_ws "$ADD3"
 run git commit -am 'beginning of chapter 3'
 map
 
 comment "We haven't updated the code in a while, so let's do that now."
 pcommand git rebase-update
 echo Fetching origin
-git fetch origin 2>&1 | grep -v 'stage'
+git fetch origin 2>&1 | grep -v 'stage' | sed 's+From.*+From https://upstream+'
 silent git update-ref refs/remotes/origin/master stage_2
 silent git tag -d $(git tag -l 'stage_*')
 git rebase-update --no_fetch
 
 comment "Well look at that. The CQ landed our typo and chapter2 branches "
 comment "already and git rebase-update cleaned them up for us."
 trunc_command gclient sync
 map
 
 comment "Someone on IRC mentions that they actually landed a chapter 3 already!"
 comment "We should pull their changes before continuing. Brace for"
 comment "a code conflict!"
 pcommand git rebase-update
 echo Fetching origin
-git fetch origin 2>&1 | grep -v 'stage'
+git fetch origin 2>&1 | grep -v 'stage' | sed 's+From.*+From https://upstream+'
 silent git tag -d $(git tag -l 'stage_*')
 echo Rebasing: chap2
 silent git rebase-update
 echo ... lots of output, it\'s a conflict alright :\(...
 run git diff
 
 comment "Oh, well, that's not too bad. In fact... that's a terrible chapter 3!"
 praw \$EDITOR "$WS"
 echo "... /me deletes bad chapter 3 ..."
 silent git checkout --theirs -- "$WS"
 run git add "$WS"
 run git diff --cached
 
 comment "Much better"
 run git rebase --continue
 run git rebase-update
 silent git tag -d $(git tag -l 'stage_*')
 trunc_command gclient sync
 map
 trunc_command git cl upload