Allow 4+ spaces of indentation for image options

Previously, this only supported 3.

Author: jelmer

parser/src/rst.pest

@@ -88,7 +88,7 @@ replace = { ^"replace::" ~ " "* ~ paragraph }
 
 image_directive = _{ ".." ~ PUSH(" "+) ~ image ~ DROP }
 image           =  { ^"image::" ~ line ~ image_opt_block? }
-image_opt_block = _{ PEEK[..-1] ~ PUSH("  " ~ POP) ~ image_option ~ (PEEK[..] ~ image_option)* }
+image_opt_block = _{ PEEK_ALL ~ PUSH(" "+ | "\t"+) ~ image_option ~ (PEEK_ALL ~ image_option)* }
 image_option    =  { ":" ~ image_opt_name ~ ":" ~ line }
 image_opt_name  =  { common_opt_name | "alt" | "height" | "width" | "scale" | "align" | "target" }
 

parser/src/tests.rs

@@ -423,6 +423,31 @@ fn substitution_image_with_alt() {
     };
 }
 
+#[allow(clippy::cognitive_complexity)]
+#[test]
+fn substitution_image_with_many_indents() {
+    parses_to! {
+        parser: RstParser,
+        input: "\
+.. |subst| image:: thing.png
+    :target: foo.html
+",
+        rule: Rule::document,
+        tokens: [
+            substitution_def(0, 51, [
+                substitution_name(4, 9),
+                image(11, 51, [
+                    line(18, 29, [ str(18, 28) ]),
+                    image_option(33, 51, [
+                        image_opt_name(34, 40),
+                        line(41, 51, [ str(41, 50) ]),
+                    ]),
+                ]),
+            ]),
+        ]
+    };
+}
+
 // TODO: test images
 
 #[allow(clippy::cognitive_complexity)]