[clang-tools-extra] [clang-doc] [feat] add --repository-line-prefix argument (PR #131280)

[Paul Kirth via cfe-commits]

================
@@ -57,7 +57,12 @@ static void writeFileDefinition(const ClangDocContext &CDCtx, const Location &L,
     OS << "*Defined at " << L.Filename << "#" << std::to_string(L.LineNumber)
        << "*";
   } else {
-    OS << "*Defined at [" << L.Filename << "#" << std::to_string(L.LineNumber)
+    OS << "*Defined at [" << L.Filename << "#";
+
+    if (!CDCtx.RepositoryLinePrefix) 
+      OS << StringRef{*CDCtx.RepositoryLinePrefix};  
+    
+    OS << std::to_string(L.LineNumber)
----------------
ilovepi wrote:

```suggestion
    OS << "*Defined at [" << L.Filename << "#"
      << CDCtx.RepositoryLinePrefix.value_or("")  
    << std::to_string(L.LineNumber)
```
Perhaps something like this? In any case, there isn't a need to convert the `optional<string>` into a `StringRef` here over just using the string value.

https://github.com/llvm/llvm-project/pull/131280