feat(indent): Implement basic indent for gdscript.

Indent is not handled correctly when adding new lines.
It seems that functions/loops/etc. are not recognized until they have at
least one indented block.

For example, if you enter a newline after `func foo():`, the cursor will
not be indented. If you manually indent and add a line like `pass`,
e.g.:

```
func foo():
    pass
```

now any insertions above or below `pass` will be indented correctly.
This might be an issue with the grammar, as it seems to apply to highlights
as well.

The following will not be highligted

```
func foo():
```

However, the following will be:

```
func foo():
    pass
```

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/indent/gdscript/basic_blocks.gd b/tests/indent/gdscript/basic_blocks.gd
new file mode 100644
index 000000000..3bc048543
--- /dev/null
+++ b/tests/indent/gdscript/basic_blocks.gd
@@ -0,0 +1,16 @@
+extends Node
+
+func _ready():
+	var x := 2
+	for i in range(x):
+		prints(i)
+
+	while x > 0:
+		print(x)
+
+	if x > 0:
+		print("if test")
+	elif x < 0:
+		print("if test")
+	else:
+		print("if test")