AK: Replace the mutable String::replace API with an immutable version

This removes the awkward String::replace API which was the only String
API which mutated the String and replaces it with a new immutable
version that returns a new String with the replacements applied. This
also fixes a couple of UAFs that were caused by the use of this API.

As an optimization an equivalent StringView::replace API was also added
to remove an unnecessary String allocations in the format of:
`String { view }.replace(...);`

1 files changed, 1 insertions, 2 deletions

diff --git a/Userland/DevTools/HackStudio/ProjectTemplate.cpp b/Userland/DevTools/HackStudio/ProjectTemplate.cpp
index 9cb202087e..619d042e5e 100644
--- a/Userland/DevTools/HackStudio/ProjectTemplate.cpp
+++ b/Userland/DevTools/HackStudio/ProjectTemplate.cpp
@@ -90,8 +90,7 @@ Result<void, String> ProjectTemplate::create_project(const String& name, const S
         dbgln("Running post-create script '{}'", postcreate_script_path);
 
         // Generate a namespace-safe project name (replace hyphens with underscores)
-        String namespace_safe(name.characters());
-        namespace_safe.replace("-", "_", true);
+        auto namespace_safe = name.replace("-", "_", true);
 
         pid_t child_pid;
         const char* argv[] = { postcreate_script_path.characters(), name.characters(), path.characters(), namespace_safe.characters(), nullptr };