refactor: Rename and move const_arg_path

It wasn't testing the `const_arg` code path, it was actually hitting
const_param's default value code path, so move it to the right place
and rename it.

crates/parser/test_data/parser/inline/ok/0188_const_arg_path.rast

@@ -1,30 +0,0 @@
-SOURCE_FILE
-  TYPE_ALIAS
-    TYPE_KW "type"
-    WHITESPACE " "
-    NAME
-      IDENT "T"
-    WHITESPACE " "
-    EQ "="
-    WHITESPACE " "
-    PATH_TYPE
-      PATH
-        PATH_SEGMENT
-          NAME_REF
-            IDENT "S"
-          GENERIC_ARG_LIST
-            L_ANGLE "<"
-            TYPE_ARG
-              PATH_TYPE
-                PATH
-                  PATH
-                    PATH_SEGMENT
-                      NAME_REF
-                        IDENT "u32"
-                  COLON2 "::"
-                  PATH_SEGMENT
-                    NAME_REF
-                      IDENT "MAX"
-            R_ANGLE ">"
-    SEMICOLON ";"
-  WHITESPACE "\n"

crates/parser/test_data/parser/inline/ok/0188_const_arg_path.rs

@@ -1 +0,0 @@
-type T = S<u32::MAX>;

crates/parser/test_data/parser/inline/ok/0188_const_param_default_path.rast

@@ -0,0 +1,36 @@
+SOURCE_FILE
+  STRUCT
+    STRUCT_KW "struct"
+    WHITESPACE " "
+    NAME
+      IDENT "A"
+    GENERIC_PARAM_LIST
+      L_ANGLE "<"
+      CONST_PARAM
+        CONST_KW "const"
+        WHITESPACE " "
+        NAME
+          IDENT "N"
+        COLON ":"
+        WHITESPACE " "
+        PATH_TYPE
+          PATH
+            PATH_SEGMENT
+              NAME_REF
+                IDENT "i32"
+        WHITESPACE " "
+        EQ "="
+        WHITESPACE " "
+        PATH_EXPR
+          PATH
+            PATH
+              PATH_SEGMENT
+                NAME_REF
+                  IDENT "i32"
+            COLON2 "::"
+            PATH_SEGMENT
+              NAME_REF
+                IDENT "MAX"
+      R_ANGLE ">"
+    SEMICOLON ";"
+  WHITESPACE "\n"

crates/parser/test_data/parser/inline/ok/0188_const_param_default_path.rs

@@ -0,0 +1 @@
+struct A<const N: i32 = i32::MAX>;