namcap: add page (#6722)

pages/linux/namcap.md

@@ -0,0 +1,16 @@
+# namcap
+
+> Check binary packages and source `PKGBUILD`s for common packaging mistakes.
+> More information: <https://man.archlinux.org/man/namcap.1>.
+
+- Check a specific `PKGBUILD` file:
+
+`namcap {{path/to/pkgbuild}}`
+
+- Check a specific package file:
+
+`namcap {{path/to/package.pkg.tar.zst}}`
+
+- Check a file, printing extra [i]nformational messages:
+
+`nnamcap -i {{path/to/file}}`