Calls the completion-function in a text-input-pane.
capi
text-input-pane-complete-text pane => result
| pane⇩ | 
| result⇩ | 
A string, or  nil. | 
The function text-input-pane-complete-text calls the completion-function of pane with the current text. If this call is successful, then the text of pane is set to the result, and text-input-pane-complete-text returns this result. Otherwise, result is nil.
Note: the completion-function may return a list of completion candidates, in which case text-input-pane-complete-text prompts the user to select one of the candidates.
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:32:42