Fix ambiguous overload resolution

One operator+ for CBotString is enough

src/CBot/CBotDll.h

@@ -397,7 +397,6 @@ public:
     const CBotString& operator=(const CBotString& stringSrc);
     const CBotString& operator=(const char ch);
     const CBotString& operator=(const char* pString);
-    friend CBotString operator+(const CBotString& string, const char* lpsz);
     CBotString operator+(const CBotString& str);
 
     const CBotString& operator+=(const char ch);

src/CBot/CBotFunction.cpp

@@ -216,7 +216,7 @@ CBotFunction* CBotFunction::Compile(CBotToken* &p, CBotCStack* pStack, CBotFunct
 
         if ( IsOfType(p, ID_NOT) )
         {
-            CBotToken d("~" + p->GetString());
+            CBotToken d(CBotString("~") + p->GetString());
             func->m_token = d;
         }
 

src/CBot/CBotString.cpp

@@ -337,13 +337,6 @@ const CBotString& CBotString::operator=(const CBotString& stringSrc)
     return *this;
 }
 
-CBotString operator+(const CBotString& string, const char * lpsz)
-{
-    CBotString s(string);
-    s += lpsz;
-    return s;
-}
-
 CBotString CBotString::operator+(const CBotString& stringSrc)
 {
     CBotString s(*this);

src/CBot/CBotVar.cpp

@@ -1703,7 +1703,7 @@ void CBotVarClass::DecrementUse()
             pThis->SetPointer(this);
             CBotVar*    pResult = nullptr;
 
-            CBotString    nom = "~" + m_pClass->GetName();
+            CBotString    nom = CBotString("~") + m_pClass->GetName();
             long        ident = 0;
 
             while ( pile->IsOk() && !m_pClass->ExecuteMethode(ident, nom, pThis, ppVars, pResult, pile, nullptr)) ;    // waits for the end

test/unit/CBot/CBotString_test.cpp

@@ -277,9 +277,6 @@ TEST(CBotString_Test, operatorAdd)
     botStr1 = botStr1 + botStr3;
     EXPECT_STREQ(botStr1.CStr(), botStr4.CStr());
 
-    botStr1 = "C" + botStr3;
-    EXPECT_STREQ(botStr1.CStr(), botStr4.CStr());
-
     botStr1.Empty();
     botStr1 = botStr2 + cStr1;
     EXPECT_STREQ(botStr1.CStr(), botStr4.CStr());