Pass selected autocomplete option through the completer

When using 'enter' to select an autocomplete suggestion, use the
autocompleter get_completion method to get the completed text before
accepting it instead of accepting just the suggestion. This allows the
completer to offer partial suggestions instead of having to offer the
full input each time.

inquire/src/prompts/text/prompt.rs

@@ -1,4 +1,4 @@
-use std::cmp::min;
+use std::{cmp::min, borrow::Cow};
 
 use crate::{
     autocompletion::{NoAutoCompletion, Replacement},
@@ -131,26 +131,30 @@ impl<'a> TextPrompt<'a> {
         }
     }
 
-    fn get_current_answer(&self) -> &str {
+    fn get_current_answer(&mut self) -> Cow<'_, str> {
         // If there is a highlighted suggestion, assume user wanted it as
         // the answer.
-        if let Some(suggestion) = self.get_highlighted_suggestion() {
-            return suggestion;
+        let opt = self.get_highlighted_suggestion();
+        if let Some(opt) = opt {
+            if let Ok(Some(value)) = self.autocompleter.get_completion(self.input.content(), Some(opt.into())) {
+                return value.into();
+            }
         }
 
         // Empty input with default values override any validators.
         if self.input.content().is_empty() {
             if let Some(val) = self.default {
-                return val;
+                return val.into();
             }
         }
 
-        self.input.content()
+        self.input.content().into()
     }
 
-    fn validate_current_answer(&self) -> InquireResult<Validation> {
+    fn validate_current_answer(&mut self) -> InquireResult<Validation> {
+        let answer = self.get_current_answer().into_owned();
         for validator in &self.validators {
-            match validator.validate(self.get_current_answer()) {
+            match validator.validate(&answer) {
                 Ok(Validation::Valid) => {}
                 Ok(Validation::Invalid(msg)) => return Ok(Validation::Invalid(msg)),
                 Err(err) => return Err(InquireError::Custom(err)),
@@ -194,7 +198,7 @@ where
             }
         };
 
-        Ok(result)
+        Ok(result.map(|r|r.into()))
     }
 
     fn handle(&mut self, action: TextPromptAction) -> InquireResult<ActionResult> {