Mishandles branch names containing #

[wjt]

On endlessm/threadbare#1466 (comment) we found that:

a. It is possible to use # in the name of git branches
b. This is mishandled by amalgamate-pages. For instance it posts comments like this:

Play this branch at https://play.threadbare.game/branches/endlessm/#1272_Storybook_Redisign.

but this link does not work because # has special meaning in URLs.

[wjt]

I tested this in this PR:

• Test commit for awkward branch name amalgamate-pages-test#17

The playable URL for the branch is:

https://endlessm.github.io/amalgamate-pages-test/branches/endlessm/awkward-chars-%27/%25-%23/

https://endlessm.github.io/amalgamate-pages-test/branches/ correctly handles this.

The comment does not:

Play this branch at https://endlessm.github.io/amalgamate-pages-test/branches/endlessm/awkward-chars-'/%-#/.