[libraries/ktextaddons] textcustomeditor/plaintexteditor: Revert this part of previous patch

Git commit 3c74ceda72d2de50b71388724d87b2aec0d07be4 by Laurent Montel.
Committed on 09/08/2026 at 20:51.
Pushed by mlaurent into branch 'master'.

Revert this part of previous patch

M  +3    -1    textcustomeditor/plaintexteditor/plaintextsyntaxspellcheckinghighlighter.cpp

https://invent.kde.org/libraries/ktextaddons/-/commit/3c74ceda72d2de50b71388724d87b2aec0d07be4

diff --git a/textcustomeditor/plaintexteditor/plaintextsyntaxspellcheckinghighlighter.cpp b/textcustomeditor/plaintexteditor/plaintextsyntaxspellcheckinghighlighter.cpp
index 26788234f..7461c8ef8 100644
--- a/textcustomeditor/plaintexteditor/plaintextsyntaxspellcheckinghighlighter.cpp
+++ b/textcustomeditor/plaintexteditor/plaintextsyntaxspellcheckinghighlighter.cpp
@@ -157,7 +157,9 @@ void PlainTextSyntaxSpellCheckingHighlighter::setMisspelled(int start, int count
 void PlainTextSyntaxSpellCheckingHighlighter::applyFormat(int offset, int length, const KSyntaxHighlighting::Format &format)
 {
     if (format.spellCheck() && length > 0) {
-        if (d->spellCheckRanges.back().end() + 1 == offset) {
+        if (d->spellCheckRanges.empty()) {
+            d->spellCheckRanges.emplace_back(offset, length);
+        } else if (d->spellCheckRanges.back().end() + 1 == offset) {
             d->spellCheckRanges.back().length += length;
         } else {
             d->spellCheckRanges.emplace_back(offset, length);