Improve indentation of blocks inside if/while headers

Fixes #1665

fish_indent.cpp

@@ -84,10 +84,11 @@ static void prettify_node_recursive(const wcstring &source, const parse_node_tre
     const parse_node_t &node = tree.at(node_idx);
     const parse_token_type_t node_type = node.type;
 
-    /* Increment the indent if we are either a root job_list, or root case_item_list */
+    /* Increment the indent if we are either a root job_list, or root case_item_list, or in an if or while header (#1665) */
     const bool is_root_job_list = (node_type == symbol_job_list && parent_type != symbol_job_list);
     const bool is_root_case_item_list = (node_type == symbol_case_item_list && parent_type != symbol_case_item_list);
-    if (is_root_job_list || is_root_case_item_list)
+    const bool is_if_while_header = (node_type == symbol_job && (parent_type == symbol_if_clause || parent_type == symbol_while_header));
+    if (is_root_job_list || is_root_case_item_list || is_if_while_header)
     {
         node_indent += 1;
     }

tests/indent.in

@@ -75,4 +75,11 @@ echo hi
 else
 echo bye
 end; echo alpha "
-' | ../fish_indent
+' | ../fish_indent
+
+echo \nTest7
+# issue 1665
+echo -n '
+if begin ; false; end; echo hi ; end
+while begin ; false; end; echo hi ; end
+' | ../fish_indent

tests/indent.out

@@ -78,3 +78,16 @@ else
 echo bye
 end
 echo alpha "
+
+Test7
+
+if begin
+        false
+    end
+    echo hi
+end
+while begin
+        false
+    end
+    echo hi
+end