doc: interpret-trailers: don’t use heredoc in examples

This file contains four instances of trailing spaces from its inception
in commit [1]. These spaces might be intentional, since a user would be
prompted with `> ` in an interactive session. On the one hand, this is a
whitespace error according to `git diff --check`; on the other hand, the
raw documentation—it makes no difference in the rendered output—is just
staying faithful to the simulation of the interactive prompt.

Let’s get rid of these whitespace errors and also make the examples more
friendly to cut-and-paste by replacing the heredocs with files which are
shown with cat(1).

[1]: dfd66ddf5a (Documentation: add documentation for 'git
    interpret-trailers', 2014-10-13)

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-interpret-trailers.txt

@@ -326,13 +326,12 @@ $ git config trailer.sign.key "Signed-off-by: "
 $ git config trailer.sign.ifmissing add
 $ git config trailer.sign.ifexists doNothing
 $ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"'
-$ git interpret-trailers <<EOF
-> EOF
+$ git interpret-trailers </dev/null
 
 Signed-off-by: Bob <bob@example.com>
-$ git interpret-trailers <<EOF
-> Signed-off-by: Alice <alice@example.com>
-> EOF
+$ cat msg.txt
+Signed-off-by: Alice <alice@example.com>
+$ git interpret-trailers <msg.txt
 
 Signed-off-by: Alice <alice@example.com>
 ------------
@@ -357,15 +356,14 @@ Fix #42
 $ cat ~/bin/glog-find-author
 #!/bin/sh
 test -n "$1" && git log --author="$1" --pretty="%an <%ae>" -1 || true
+$ cat msg.txt
+subject
+
+message
 $ git config trailer.help.key "Helped-by: "
 $ git config trailer.help.ifExists "addIfDifferentNeighbor"
 $ git config trailer.help.cmd "~/bin/glog-find-author"
-$ git interpret-trailers --trailer="help:Junio" --trailer="help:Couder" <<EOF
-> subject
->
-> message
->
-> EOF
+$ git interpret-trailers --trailer="help:Junio" --trailer="help:Couder" <msg.txt
 subject
 
 message
@@ -382,15 +380,14 @@ Helped-by: Christian Couder <christian.couder@gmail.com>
 $ cat ~/bin/glog-grep
 #!/bin/sh
 test -n "$1" && git log --grep "$1" --pretty=reference -1 || true
+$ cat msg.txt
+subject
+
+message
 $ git config trailer.ref.key "Reference-to: "
 $ git config trailer.ref.ifExists "replace"
 $ git config trailer.ref.cmd "~/bin/glog-grep"
-$ git interpret-trailers --trailer="ref:Add copyright notices." <<EOF
-> subject
->
-> message
->
-> EOF
+$ git interpret-trailers --trailer="ref:Add copyright notices." <msg.txt
 subject
 
 message
@@ -402,17 +399,17 @@ Reference-to: 8bc9a0c769 (Add copyright notices., 2005-04-07)
   commit that is related, and show how it works:
 +
 ------------
+$ cat msg.txt
+subject
+
+message
+
+see: HEAD~2
 $ git config trailer.see.key "See-also: "
 $ git config trailer.see.ifExists "replace"
 $ git config trailer.see.ifMissing "doNothing"
 $ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG"
-$ git interpret-trailers <<EOF
-> subject
-> 
-> message
-> 
-> see: HEAD~2
-> EOF
+$ git interpret-trailers <msg.txt
 subject
 
 message
@@ -427,22 +424,21 @@ See-also: fe3187489d69c4 (subject of related commit)
   to add a 'git-version' trailer:
 +
 ------------
-$ sed -e 's/ Z$/ /' >commit_template.txt <<EOF
-> ***subject***
-> 
-> ***message***
-> 
-> Fixes: Z
-> Cc: Z
-> Reviewed-by: Z
-> Signed-off-by: Z
-> EOF
+$ cat temp.txt
+***subject***
+
+***message***
+
+Fixes: Z
+Cc: Z
+Reviewed-by: Z
+Signed-off-by: Z
+$ sed -e 's/ Z$/ /' temp.txt > commit_template.txt
 $ git config commit.template commit_template.txt
-$ cat >.git/hooks/commit-msg <<EOF
-> #!/bin/sh
-> git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new"
-> mv "\$1.new" "\$1"
-> EOF
+$ cat .git/hooks/commit-msg
+#!/bin/sh
+git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new"
+mv "\$1.new" "\$1"
 $ chmod +x .git/hooks/commit-msg
 ------------