Move editor.c: is_{string,comment,code}_style() functions to
highlighting.c, add to API.
Add editor_find_snippet(), editor_insert_snippet(),
utils_find_open_xml_tag() to API.



git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@5409 ea778897-0a13-0410-b9d1-a72fbfd435f5