[emscripten] Link to README from emcc --use-port=emdawnwebgpu:help

This makes emcc --use-port=emdawnwebgpu:help point directly at the
README file, and shortens the prose description as all that other info
is in the readme.

emdawnwebgpu (--use-port=emdawnwebgpu; Some files: BSD 3-Clause License. Other files: Emscripten's license (available under both MIT License and University of Illinois/NCSA Open Source License))
Emdawnwebgpu implements webgpu.h on WebGPU, replacing -sUSE_WEBGPU. **For info on usage and filing feedback, see link below.**
Options:
* cpp_bindings: Add the include path for Dawn-like <webgpu/webgpu_cpp.h> C++ bindings. Default: true.
* opt_level: Optimization (-O) level for the bindings' Wasm layer. Default: choose based on -sASSERTIONS.
* shared_memory: Enable -sSHARED_MEMORY. Default: choose based on whether linker has -sSHARED_MEMORY enabled.
More info: https://dawn.googlesource.com/dawn/+/8c096fd9f643c8dc03639c127eb9593e4f5681fb/src/emdawnwebgpu/pkg/README.md

No-Try: true
Change-Id: Ib0e9be50ddf773df38f7e1952db5546ead806700
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/245195
Reviewed-by: Loko Kung <lokokung@google.com>
Auto-Submit: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Loko Kung <lokokung@google.com>
diff --git a/.github/workflows/package-emdawnwebgpu.sh b/.github/workflows/package-emdawnwebgpu.sh
index 5d2d5b6..c1adc03 100755
--- a/.github/workflows/package-emdawnwebgpu.sh
+++ b/.github/workflows/package-emdawnwebgpu.sh
@@ -76,6 +76,7 @@
 # University of Illinois/NCSA Open Source License.  Both these licenses can be
 # found in the LICENSE file.
 
+# https://dawn.googlesource.com/dawn/+/${SHA}/src/emdawnwebgpu/pkg/README.md
 r"""
 $(cat out/wasm/emdawnwebgpu_pkg/README.md)
 """
@@ -87,9 +88,13 @@
 PORT_FILE = 'emdawnwebgpu_pkg/emdawnwebgpu.port.py'
 
 # Port information (required)
-URL = 'https://dawn.googlesource.com/dawn/+/refs/heads/main/src/emdawnwebgpu/'
-DESCRIPTION = "Emdawnwebgpu is a fork of Emscripten's original USE_WEBGPU, implementing a newer, more stable version of the standardized webgpu.h interface."
+
+# - Visible in emcc --show-ports and emcc --use-port=emdawnwebgpu:help
 LICENSE = "Some files: BSD 3-Clause License. Other files: Emscripten's license (available under both MIT License and University of Illinois/NCSA Open Source License)"
+
+# - Visible in emcc --use-port=emdawnwebgpu:help
+DESCRIPTION = "Emdawnwebgpu implements webgpu.h on WebGPU, replacing -sUSE_WEBGPU. **For info on usage and filing feedback, see link below.**"
+URL = 'https://dawn.googlesource.com/dawn/+/${SHA}/src/emdawnwebgpu/pkg/README.md'
 EOF
 
 # Create RELEASE_INFO.md
diff --git a/src/emdawnwebgpu/README.md b/src/emdawnwebgpu/README.md
index cb6a0b6..2478129 100644
--- a/src/emdawnwebgpu/README.md
+++ b/src/emdawnwebgpu/README.md
@@ -18,7 +18,8 @@
 ## Using emdawnwebgpu pre-built releases
 
 Pre-built releases are published at <https://github.com/google/dawn/releases>.
-See the [included README](./pkg/README.md) on how to use them.
+
+**See the [included README](./pkg/README.md) on how to use them.**
 
 TODO(crbug.com/371024051): Link to a sample project in that README.