feat: add ability to override wasm_file (#46)

* feat: add ability to override `wasm_file`

* fix: renamed wasm_file to fish_wasm_file in ./scripts/build-fish-wasm.fish

---------

Co-authored-by: ndonfris <ndonfris29@gmail.com>

scripts/build-fish-wasm.fish

@@ -1,8 +1,9 @@
 #!/usr/bin/env fish
 
-set -l wasm_file "$(find node_modules -type f -a -name tree-sitter-fish.wasm)" 
+# fish_wasm_file is only used in the nixos build step, and should otherwise be ignored 
+not set -q fish_wasm_file; and set -l fish_wasm_file "$(find node_modules -type f -a -name tree-sitter-fish.wasm)"
 
-if test -z "$wasm_file"
+if test -z "$fish_wasm_file"
     yarn add @esdmr/tree-sitter-fish
     echo "ERROR: 'tree-sitter-fish.wasm' not found"
     echo -e "try installing:\t@esdmr/tree-sitter-fish"
@@ -13,5 +14,5 @@ if test -z "$wasm_file"
     exit 1
 end
 
-cp -f "$wasm_file" . 
-and echo "SUCCESS: tree-sitter-fish.wasm copied"
+cp -f "$fish_wasm_file" . 
+and echo "SUCCESS: tree-sitter-fish.wasm copied from location '$fish_wasm_file'"