update doc

Author: Kivooeo

src/appendix/humorust.md

@@ -3,7 +3,7 @@
 What's a project without a sense of humor? And frankly some of these are
 enlightening?
 
-- [Weird exprs test](https://github.com/rust-lang/rust/blob/master/tests/ui/weird-exprs.rs)
+- [Weird exprs test](https://github.com/rust-lang/rust/blob/master/tests/ui/expr/weird-exprs.rs)
 - [Ferris Rap](https://fitzgen.com/2018/12/13/rust-raps.html)
 - [The Genesis of Generic Germination](https://github.com/rust-lang/rust/pull/53645#issue-210543221)
 - [The Bastion of the Turbofish test](https://github.com/rust-lang/rust/blob/79d8a0fcefa5134db2a94739b1d18daa01fc6e9f/src/test/ui/bastion-of-the-turbofish.rs)

src/tests/directives.md

@@ -359,7 +359,7 @@ described below:
   - Example: `x86_64-unknown-linux-gnu`
 
 See
-[`tests/ui/commandline-argfile.rs`](https://github.com/rust-lang/rust/blob/master/tests/ui/argfile/commandline-argfile.rs)
+[`tests/ui/argfile/commandline-argfile.rs`](https://github.com/rust-lang/rust/blob/master/tests/ui/argfile/commandline-argfile.rs)
 for an example of a test that uses this substitution.
 
 [output normalization]: ui.md#normalization

src/tests/ui.md

@@ -25,9 +25,9 @@ If you need to work with `#![no_std]` cross-compiling tests, consult the
 
 ## General structure of a test
 
-A test consists of a Rust source file located anywhere in the `tests/ui`
-directory, but they should be placed in a suitable sub-directory. For example,
-[`tests/ui/hello.rs`] is a basic hello-world test.
+A test consists of a Rust source file located in the `tests/ui` directory.
+**Tests must be placed in the appropriate subdirectory** based on their purpose
+and testing category - placing tests directly in `tests/ui` is not permitted.
 
 Compiletest will use `rustc` to compile the test, and compare the output against
 the expected output which is stored in a `.stdout` or `.stderr` file located
@@ -46,8 +46,6 @@ pass/fail expectations](#controlling-passfail-expectations).
 By default, a test is built as an executable binary. If you need a different
 crate type, you can use the `#![crate_type]` attribute to set it as needed.
 
-[`tests/ui/hello.rs`]: https://github.com/rust-lang/rust/blob/master/tests/ui/hello.rs
-
 ## Output comparison
 
 UI tests store the expected output from the compiler in `.stderr` and `.stdout`