Issues with namespace qualified function completion (variant list)

Type fn into an XQuery document. This lists functions in the fn namespace (and other functions containing fn). This is the expected behaviour. For example:
```
fn:abs
fn:adjust-date-to-timezone
fn:adjust-dateTime-to-timezone
...
```
Press the : key (so the current context is fn:). This causes the completion list box to disappear. It should list items in namespaces ending with fn (including, e.g. myfn:test, as well as fn:abs, etc.).
Type ex (so the current context is fn:ex). This lists:
```
cts:exists
dbg:expr
math:exp
exactly-one
...
fn:exactly-one
...
```
This should only list the items matching fn:ex, for example:
```
fn:exactly-one
fn:exists
```
Press ESC to dismiss the variant list, then type i (so the current context is fn:ex). This lists items matching exi not fn:exi. For example:
```
cts:exists
exists
fn:exists
xdmp:exists
...
```

ligasgr / intellij-xquery