[ox/std] Make String::beginsWtih and endsWith functions that take StringViews

deps/ox/src/ox/std/CMakeLists.txt

@@ -33,6 +33,7 @@ add_library(
 		substitutes.cpp
 		stacktrace.cpp
 		string.cpp
+		stringview.cpp
 		strops.cpp
 		trace.cpp
 		typetraits.cpp