Fix typos with codespell

Using codespell 1.14.0.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
doubleclick
lod
nd
numer
que
te
unselect
EOF
$ codespell -w -q 3 -I ../godot-word-whitelist.txt --skip="./thirdparty,*.po"
$ git diff // undo unwanted changes
```

platform/javascript/detect.py

@@ -130,7 +130,7 @@ def configure(env):
     env.Append(LINKFLAGS=['-s', 'ALLOW_MEMORY_GROWTH=1'])
 
     # Since we use both memory growth and MEMFS preloading,
-    # this avoids unecessary copying on start-up.
+    # this avoids unnecessary copying on start-up.
     env.Append(LINKFLAGS=['--no-heap-copy'])
 
     # This setting just makes WebGL 2 APIs available, it does NOT disable WebGL 1.