Remove derived PDFs from repo; now in 'src' repo, comstructed by HCFILES and MAKE-INDEX-HTMLS (#1657)

* Remove derived PDFs from branch other than gh-pages

* only the gh-pages branch should have the pdfs

* make pdfs and listings

* Update HCFILES and MAKE-INDEX-HTMLS, add preliminary documentation

* add a slashit to avoid angle brackets

scripts/make-gh-pages.md

@@ -0,0 +1,73 @@
+preliminary documentation -- needs validation
+HCFILES writes in {MEDLEYDIR} but it should write in something like (SRCDIR)
+
+# setup
+
+ github pages are maintained in the 'src' repository as a forked repo
+ If you don't have a clone of src: 
+```
+   gh repo clone interlisp/src # make one
+   cd src                      # all other commands 
+```
+the first time once you've cloned, point the 'src' clone 
+```
+   gh remote add upstream https://github.com/interlisp/medley
+
+```
+now update src repository to match 'medley'
+Run these in the 'src' repository!
+
+```
+   git fetch upstream                # pull down remote branches
+   git checkout master               # make sure you're in master
+   git rebase upstream/master        # update src's master
+                                      # to latest medley's master
+   git push -f origin master          # push back go sfc
+```
+
+# Run Medly to create PDFs.
+
+Start with the apps sysout to spare yourself package problems
+In an Interlisp exec:
+```
+  (FILESLOAD PDFSTREAM GITFNS MEDLEY-UTILS)
+  (HCFILES)
+  (MAKE-INDEX-HTMLS)
+```
+check out that it looks right if you point your browser the index/index.hrml at the top level
+
+# deploying
+
+* find the current release tags
+Not sure how to do that.
+
+```
+   wget -l 1 https://github.com/interlisp/medley/releases/latest
+```
+will retrieve a 3xx redirect from the web server;
+But all you need is the name, not the web page.
+anyway, assuming the release is medley-YYMMDD-xxxxxxx. 
+
+put release name in variable
+```
+  export release=medley-240420-1234567
+```
+## make a new branch
+```
+   git checkout -b pages-$release
+```
+*temporarily* change .gitignore to allow checkin of pdfs and index.html
+```
+cp .gitignore /tmp/save$release
+cp .gitignore.for.pages .gitignore
+```
+Now you can push this to the github-pages
+```
+	git add .
+	git commit -m "rerun making ghpages and index"
+	git push
+```
+
+
+
+