Issue: #2192

Motivation for this change

Unwanted removal of \n characters in Org Roam template strings.

org-capture-fill-template fills the template string, but it removes whitespace and newlines at the beginning and end of the template.*

org-roam-capture--fill-template removes all blank lines and restores them after calling org-capture-fill-template.

The regex formula used for this however (\n$) eliminates all blank lines in the template, whether or not they are at the beginning and end of the template.

By replacing it with [\n]*\\' only the blank lines at the end of the template will be removed -only the ones which will be later restored.

Example

With a default template as follows:

(setq org-roam-capture-templates
      '(("d" "default" plain "%?"
	    :target (file+head "%<%Y%m%d%H%M%S>-${slug}.org"
			       "#+STARTUP: overview\n\n\n\n#+title:${title}\n\n\n")
	    :unnarrowed t)))

org-roam-capture--fill-template would previously output

"#+STARTUP: overview#+title:${title}\n\n\n"

while with the new formula it outputs (the user's input as would be expected)

"#+STARTUP: overview\n\n\n#+title:${title}\n\n\n"

*: paraphrased from the comment in org-roam-capture--fill-template