Reduce side effects on options in screen reader mode

We don't need to disable predictions or the continuation prompt in the options,
since with tests we can verify the few places we need to check.

Author: andyleejordan

PSReadLine/Options.cs

@@ -188,14 +188,6 @@ private void SetOptionsInternal(SetPSReadLineOption options)
             if (options._enableScreenReaderMode.HasValue)
             {
                 Options.ScreenReaderModeEnabled = options.EnableScreenReaderMode;
-
-                if (Options.ScreenReaderModeEnabled)
-                {
-                    // Disable prediction for better accessibility.
-                    Options.PredictionSource = PredictionSource.None;
-                    // Disable continuation prompt as multi-line is not available.
-                    Options.ContinuationPrompt = "";
-                }
             }
         }
 

PSReadLine/Render.cs

@@ -286,6 +286,10 @@ static int FindCommonPrefixLength(string leftStr, string rightStr)
 
             // For screen readers, we are just comparing the previous and current buffer text
             // (without colors) and only writing the differences.
+            //
+            // Note that we don't call QueryForSuggestion() which is the only
+            // entry into the prediction logic, so while it could be enabled, it
+            // won't do anything in this rendering implementation.
             string parsedInput = ParseInput();
             StringBuilder buffer = new(parsedInput);
 
@@ -1348,7 +1352,9 @@ internal Point ConvertOffsetToPoint(int offset, StringBuilder buffer = null)
             int y = _initialY;
 
             int bufferWidth = _console.BufferWidth;
-            var continuationPromptLength = LengthInBufferCells(Options.ContinuationPrompt);
+            var continuationPromptLength = Options.ScreenReaderModeEnabled
+                ? 0
+                : LengthInBufferCells(Options.ContinuationPrompt);
 
             for (int i = 0; i < offset; i++)
             {
@@ -1400,7 +1406,10 @@ private int ConvertLineAndColumnToOffset(Point point)
             int y = _initialY;
 
             int bufferWidth = _console.BufferWidth;
-            var continuationPromptLength = LengthInBufferCells(Options.ContinuationPrompt);
+            var continuationPromptLength = Options.ScreenReaderModeEnabled
+                ? 0
+                : LengthInBufferCells(Options.ContinuationPrompt);
+
             for (offset = 0; offset < _buffer.Length; offset++)
             {
                 // If we are on the correct line, return when we find

test/UnitTestReadLine.cs

@@ -644,7 +644,9 @@ private void TestSetup(TestConsole console, KeyMode keyMode, params KeyHandler[]
             PSConsoleReadLine.SetOptions(colorOptions);
 
             // Cache the continuation prompt length for use in tests
-            _continuationPromptLength = PSConsoleReadLine.GetOptions().ContinuationPrompt.Length;
+            _continuationPromptLength = ScreenReaderModeEnabled
+                ? 0
+                : PSConsoleReadLine.GetOptions().ContinuationPrompt.Length;
 
             if (!_oneTimeInitCompleted)
             {