docs(middleware): clarify MethodOverrideGetter return value (#3059)

* fix(middleware): normalize MethodOverride method to uppercase

Overridden methods such as "delete" did not match router http.Method*
constants. Trim and uppercase the override value before assigning.

* docs(middleware): clarify MethodOverrideGetter return value

Per review: do not normalize override methods in middleware. Document that
Getter should return a standard method name (e.g. http.MethodDelete).

Author: sonnemusk

middleware/method_override.go

@@ -19,7 +19,10 @@ type MethodOverrideConfig struct {
 	Getter MethodOverrideGetter
 }
 
-// MethodOverrideGetter is a function that gets overridden method from the request
+// MethodOverrideGetter is a function that gets overridden method from the request.
+// The returned value should be a standard HTTP method name as used by net/http
+// (e.g. http.MethodDelete, "DELETE"). The middleware does not normalize case or
+// trim spaces — callers / Getter implementations should return a valid method.
 type MethodOverrideGetter func(c *echo.Context) string
 
 // DefaultMethodOverrideConfig is the default MethodOverride middleware config.