refactor: rename file

PR-URL: #6128
Reviewed-by: Athan Reines <kgryte@gmail.com>

Author: gururaj1512

lib/node_modules/@stdlib/number/float64/base/identity/manifest.json

@@ -28,7 +28,7 @@
     {
       "task": "build",
       "src": [
-        "./src/identity.c"
+        "./src/main.c"
       ],
       "include": [
         "./include"
@@ -42,7 +42,7 @@
     {
       "task": "benchmark",
       "src": [
-        "./src/identity.c"
+        "./src/main.c"
       ],
       "include": [
         "./include"
@@ -54,7 +54,7 @@
     {
       "task": "examples",
       "src": [
-        "./src/identity.c"
+        "./src/main.c"
       ],
       "include": [
         "./include"