Use accented characters' ASCII versions in default branch names

When creating a branch by clicking the "Create branch" button on the sidebar of a Jira issue, the summary of the issue is passed in the issueSummary URL parameter and is used as the default name of the newly created branch. During processing of this URL parameter, any non-ASCII characters get removed from it, which sometimes results in unreadable branch names, especially in diacritics-heavy languages.

I suggest instead of removing these characters to try to convert them to their accentless ASCII alternatives (e.g. ó,ö,ő,õ… → o).