Fix typos with codespell

Using codespell 1.17.1.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
curvelinear
dof
doubleclick
fave
findn
leapyear
lod
merchantibility
nd
numer
ois
ony
que
seeked
synching
te
uint
unselect
webp
EOF

$ codespell -w -q 3 -I ../godot-word-whitelist.txt --skip="./thirdparty,*.po"
$ git diff // undo unwanted changes
```

servers/visual/shader_language.cpp

@@ -3650,7 +3650,7 @@ ShaderLanguage::Node *ShaderLanguage::_parse_expression(BlockNode *p_block, cons
 				}
 			}
 
-			//consecutively do unary opeators
+			//consecutively do unary operators
 			for (int i = expr_pos - 1; i >= next_op; i--) {
 
 				OperatorNode *op = alloc_node<OperatorNode>();