Improve Special Character Handling in Obsidian Note Titles

[AltoRetrato]

Obsidian note titles can't have the special characters * " \ / < > : | ? because a note title also serves as its file name. Emoji in file names might not be supported as well (e.g., when using Dropbox to sync the Obsidian vault). Currently, the Importer just removes these special characters, but better alternatives would be:

1. Allow the user to choose a custom replacement character or string (e.g., - _ --) for these special characters, and, if the user wants, replace emojis as well.
2. Replace the special characters with similar-looking Unicode or ASCII characters, such as ✱ ✲ ＊ ⁎ ※ ' “ ” ⧵ ∖ ＼ ∕ ⁄ ‹ ⟨ 〈 ❮ › ⟩ 〉 ❯ ∶ ꞉ ː ։ ∣ ¦ ┃ ǀ ｜ ？

(FWIW, I tried importing the notes with Yarle, which has a "Global search and replace (regexp) in note title and content" feature, but it didn't work for me.)