Fix a couple of implicit type conversion warnings

Author: doxygen

src/commentcnv.l

@@ -1624,7 +1624,7 @@ static void replaceCommentMarker(yyscan_t yyscanner,std::string_view s)
   }
   // copy comment line to output
   yyextra->outBuf+=s.substr(p);
-  yyextra->col+=s.substr(p).length();
+  yyextra->col+=static_cast<int>(s.substr(p).length());
 }
 
 static inline int computeIndent(const char *s)
@@ -1849,7 +1849,7 @@ static void insertCommentStart(yyscan_t yyscanner)
   if (static_cast<int>(marker.length())<=markerSpace && !yyextra->firstIncludeLine)
   {
     copyToOutput(yyscanner,marker);
-    i+=marker.length();
+    i+=static_cast<int>(marker.length());
   }
   for (;i<contentCol;i++)
   {

src/markdown.cpp

@@ -1755,7 +1755,7 @@ int Markdown::Private::processCodeSpan(std::string_view data,size_t offset)
     if (nb>=3) // found ``` that is not at the start of the line, keep it as-is.
     {
       out+=data.substr(0,nb);
-      return nb;
+      return static_cast<int>(nb);
     }
     return 0;  // no matching delimiter
   }

src/regex.cpp

@@ -286,7 +286,7 @@ void Ex::Private::compile()
           prevTokenPos = tokenPos;
           addToken(PToken(PToken::Kind::BeginCapture));
           size_t id = ++nextCaptureId; // groups start at 1, 0 is whole match
-          data.back().setValue(id);
+          data.back().setValue(static_cast<uint16_t>(id));
           captureStack.push_back(id);
         }
         break;
@@ -301,7 +301,7 @@ void Ex::Private::compile()
           size_t id = captureStack.back();
           captureStack.pop_back();
           addToken(PToken(PToken::Kind::EndCapture));
-          data.back().setValue(id);
+          data.back().setValue(static_cast<uint16_t>(id));
         }
         break;
       case '[': // character class