fix previous commit

Support simple character deletion operations in StructuredTextTarget.h
to support opcode suffix modification.

src/ui/FunctionViewWidget.cpp

@@ -47,7 +47,12 @@ void FunctionViewWidget::prtt(const QString &s)
     collected_text+=s;
     //collected_text+="<br>";
 }
-
+void FunctionViewWidget::delChars(int v) {
+    assert(v>0);
+    collected_text = collected_text.remove(collected_text.size()-v,v);
+    while(v--)
+        m_doc_cursor->deletePreviousChar();
+}
 void FunctionViewWidget::addEOL()
 {
     m_doc_cursor->insertBlock(m_current_format);

src/ui/FunctionViewWidget.h

@@ -35,6 +35,7 @@ public:
     void  addEOL() override;
     void  TAGbegin(enum TAG_TYPE tag_type, void * p);
     void  TAGend(enum TAG_TYPE tag_type);
+    void  delChars(int v);
 
 
 private slots:

src/ui/StructuredTextTarget.h

@@ -6,6 +6,7 @@ public:
     virtual void TAGbegin(TAG_TYPE t,void *data)=0;
     virtual void TAGend(TAG_TYPE t)=0;
     virtual void prtt(const QString &v)=0;
+    virtual void delChars(int v) = 0;
 
     virtual void addEOL() = 0; // some targets might want to disable newlines
     void addSpace(int n=1) {