Recalled correction about line in diacritical mark (5)
I believe the answer is:
tilde
'diacritical mark' is the definition.
(tilde is a kind of diacritical mark)
'recalled correction about line' is the wordplay.
'recalled' is a reversal indicator (to recall can mean to bring something back).
'correction' becomes 'edit' (I've seen this in another clue).
'about' is an insertion indicator.
'line' becomes 'l' (used when specifying particular lines from a poem).
'edit' going around 'l' is 'edlit'.
'edlit' back-to-front is 'TILDE'.
'in' is the link.
(Other definitions for tilde that I've seen before include "what Spanish writing requires" , "Mark placed over N in Spanish" , "Spanish cedilla" , "Accent on some Spanish words" , "Accent (used over n) in Spanish and Portuguese" .)