pw_assert: Rename assert/check headers

- Rename assert.h to check.h, since it provides PW_CHECK.
- Rename light.h to assert.h, since it provides PW_ASSERT.
- Move short CHECK macros to pw_assert/short.h.
- Have light.h include assert.h and assert.h include check.h for
  backwards compatibility.

Bug: 350
Change-Id: I3ad69d1593a3ca9b8daf63aec2c849f9388aa58c
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/38720
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Wyatt Hepler <hepler@google.com>
diff --git a/pw_assert/BUILD.gn b/pw_assert/BUILD.gn
index 084aa00..5e83da1 100644
--- a/pw_assert/BUILD.gn
+++ b/pw_assert/BUILD.gn
@@ -31,15 +31,21 @@
   backend = pw_assert_BACKEND
   public_configs = [ ":default_config" ]
   public = [
-    "public/pw_assert/assert.h",
-    "public/pw_assert/internal/assert_impl.h",
+    "public/pw_assert/check.h",
+    "public/pw_assert/internal/check_impl.h",
+    "public/pw_assert/short.h",
   ]
   public_deps = [
     dir_pw_preprocessor,
 
-    # Also expose light.h to all users of pw_assert.
+    # Also expose assert.h to all users of pw_assert.
     ":light",
   ]
+
+  # TODO(pwbug/350): Allow assert.h to include check.h for backwards
+  #     compatibility. Remove this when projects have migrated.
+  allow_circular_includes_from = [ ":light" ]
+  deps = [ ":light" ]
 }
 
 # Provide a way include "pw_assert/light.h" without depending on the full
@@ -51,6 +57,7 @@
 pw_source_set("light") {
   public_configs = [ ":default_config" ]
   public = [
+    "public/pw_assert/assert.h",
     "public/pw_assert/light.h",
 
     # Needed for PW_ASSERT_ENABLE_DEBUG. Note that depending on :pw_assert to
@@ -85,7 +92,7 @@
   sources = [
     "assert_facade_test.cc",
     "fake_backend.cc",
-    "public/pw_assert/internal/assert_impl.h",
+    "public/pw_assert/internal/check_impl.h",
     "pw_assert_test/fake_backend.h",
   ]
   deps = [