fix textInsertedRange signal for insertText behind last line

wrong signal e.g. will trigger crash in word counting

#5  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#6  0x00007accf9cab393 in __pthread_kill_internal (signo=6, threadid=<optimized out>) at pthread_kill.c:78
#7  0x00007accf9c5a6c8 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#8  0x00007accf9c424b8 in __GI_abort () at abort.c:79
#9  0x00007accf9c43395 in __libc_message_impl (fmt=fmt@entry=0x7accf9dbb2ea "%s\n") at ../sysdeps/posix/libc_fatal.c:132
#10 0x00007accf9cb52a7 in malloc_printerr (str=str@entry=0x7accf9db906b "free(): invalid pointer") at malloc.c:5772
#11 0x00007accf9cb75b4 in _int_free (av=<optimized out>, p=<optimized out>, have_lock=have_lock@entry=0) at malloc.c:4507
#12 0x00007accf9cb9e93 in __GI___libc_free (mem=mem@entry=0x603abc195fa0) at malloc.c:3398
#13 0x00007accf9eaeaba in operator delete (ptr=ptr@entry=0x603abc195fa0) at /usr/src/debug/gcc/gcc/libstdc++-v3/libsupc++/del_op.cc:49
#14 0x00007accf9eaeaca in operator delete (ptr=ptr@entry=0x603abc195fa0) at /usr/src/debug/gcc/gcc/libstdc++-v3/libsupc++/del_ops.cc:33
#15 0x00007accf99e5da9 in std::__new_allocator<int>::deallocate (this=0x603abc0a8f60, __n=<optimized out>, __p=0x603abc195fa0) at /usr/include/c++/13.2.1/bits/new_allocator.h:168
#16 std::allocator<int>::deallocate (__n=<optimized out>, __p=0x603abc195fa0, this=0x603abc0a8f60, this=<optimized out>, __p=<optimized out>, __n=<optimized out>) at /usr/include/c++/13.2.1/bits/allocator.h:210
#17 std::allocator_traits<std::allocator<int> >::deallocate (__n=<optimized out>, __p=0x603abc195fa0, __a=..., __a=<optimized out>, __p=<optimized out>, __n=<optimized out>) at /usr/include/c++/13.2.1/bits/alloc_traits.h:516
#18 std::_Vector_base<int, std::allocator<int> >::_M_deallocate (__n=<optimized out>, __p=0x603abc195fa0, this=0x603abc0a8f60, this=<optimized out>, __p=<optimized out>, __n=<optimized out>) at /usr/include/c++/13.2.1/bits/stl_vector.h:387
#19 std::vector<int, std::allocator<int> >::_M_fill_insert (__x=<optimized out>, __n=<optimized out>, __position=Python Exception <class 'gdb.error'>: value has been optimized out
, this=0x603abc0a8f60) at /usr/include/c++/13.2.1/bits/vector.tcc:621
#20 std::vector<int, std::allocator<int> >::insert (__x=<optimized out>, __n=<optimized out>, __position=Python Exception <class 'gdb.error'>: value has been optimized out
, this=0x603abc0a8f60) at /usr/include/c++/13.2.1/bits/stl_vector.h:1437
#21 WordCounter::textInserted (this=0x603abc0a8f50, range=...) at /usr/src/debug/ktexteditor/ktexteditor-6.0.0/src/view/wordcounter.cpp:43
#22 0x00007accfa390ca9 in QtPrivate::QSlotObjectBase::call (a=0x7ffeb0f0f780, r=0x603abc0a8f50, this=0x603abc0a8b80, this=<optimized out>, r=<optimized out>, a=<optimized out>) at /usr/src/debug/qt6-base/qtbase-everywhere-src-6.6.2/src/corelib/kernel/qobjectdefs_impl.h:433
#23 doActivate<false> (sender=0x7accec014ce0, signal_index=40, argv=0x7ffeb0f0f780) at /usr/src/debug/qt6-base/qtbase-everywhere-src-6.6.2/src/corelib/kernel/qobject.cpp:4039
#24 0x00007accf98fe6a1 in KTextEditor::DocumentPrivate::textInsertedRange (this=<optimized out>, _t1=<optimized out>, _t2=...) at /usr/src/debug/ktexteditor/build/src/KF6TextEditor_autogen/include/moc_katedocument.cpp:1269
#25 0x00007accf98ddae2 in KTextEditor::DocumentPrivate::insertText (this=0x7accec014ce0, position=..., text=..., block=<optimized out>) at /usr/src/debug/ktexteditor/ktexteditor-6.0.0/src/document/katedocument.cpp:779
#26 0x00007accf98f778a in KTextEditor::DocumentPrivate::replaceText (this=0x7accec014ce0, range=..., s=..., block=<optimized out>) at /usr/src/debug/ktexteditor/ktexteditor-6.0.0/src/include/ktexteditor/range.h:155
#27 0x00007accf0187a0b in applyEdits (doc=0x7accec014ce0, snapshot=<optimized out>, edits=<optimized out>) at /usr/src/debug/kate/kate-24.02.1/addons/lspclient/lspclientutils.cpp:46

BUG: 483363