src: fix space for module version mismatch error

PR-URL: nodejs#10606
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

src/node.cc

@@ -2412,7 +2412,7 @@ void DLOpen(const FunctionCallbackInfo<Value>& args) {
              "\nwas compiled against a different Node.js version using"
              "\nNODE_MODULE_VERSION %d. This version of Node.js requires"
              "\nNODE_MODULE_VERSION %d. Please try re-compiling or "
-             "re-installing\nthe module (for instance, using `npm rebuild` or"
+             "re-installing\nthe module (for instance, using `npm rebuild` or "
              "`npm install`).",
              *filename, mp->nm_version, NODE_MODULE_VERSION);