Update String docs (#541)

Co-authored-by: Oliver Kopp <[email protected]>

en/setup/stringeditor.md

@@ -2,13 +2,13 @@
 
 In JabRef you write the contents of all fields the same way as you would in a text editor, with one exception: to reference a string, enclose the name of the string in a set of \# characters, e.g.: '\#jan\# 1997', which will be interpreted as the string named `jan` followed by `1997`.
 
-[Strings](../advanced/strings.md) can be edited by **Library → Edit string constants** or pressing a button in the toolbar.
+[Strings](../advanced/strings.md) can be edited in the library properties, reachable through **Library → Library Properties ->  String constants**
 
 _Strings_ are the _BibTeX_ equivalent to constants in a programming language. Each string is defined with a unique _name_ and a _content_. Elsewhere in the database, the name can be used to represent the content.
 
 For instance, if many entries are from a journal with an abbreviation that may be hard to remember, such as 'J. Theor. Biol.' \(Journal of Theoretical Biology\), a string named JTB could be defined to represent the journal's name. Instead of repeating the exact journal name in each entry, the characters '\#JTB\#' \(without quotes\) are put into the _journal_ field of each, ensuring the journal name is written identically each time.
 
-A string reference can appear anywhere in a field, always by enclosing the string's name in a pair of '\#' characters. This syntax is specific for JabRef, and differs slightly from the _BibTeX_ notation that is produced when you save your database. Strings can by default be used for all standard BibTeX fields, and in **Options → Preferences → File** you can opt to enable strings for non-standard fields as well. In the latter case you can specify a set of fields that are excepted from string resolving, and here it is recommended to include the 'url' field and other fields that may need to contain the '\#' character and that may be processed by BibTeX/LaTeX.
+A string reference can appear anywhere in a field, always by enclosing the string's name in a pair of '\#' characters. This syntax is specific for JabRef, and differs slightly from the _BibTeX_ notation that is produced when you save your library. Strings can only be used for the fields defined under **File → Preferences → Entry**. You can add any other fields for which you may enable BibTeX string support. Here, you cannot use the '\#' character for processing by BibTeX/LaTeX any more.
 
 A string may in the same way be referred in the content of another string, provided the referred string is defined _before_ the referring one.