rst: fix bug 20 from #17340 (#18360)

and a leftover bug: priority of option list inside definition list

lib/packages/docutils/rst.nim

@@ -2245,7 +2245,7 @@ proc parseOptionList(p: var RstParser): PRstNode =
         popInd(p)
       else:
         parseLine(p, b)
-      if currentTok(p).kind == tkIndent: inc p.idx
+      while currentTok(p).kind == tkIndent: inc p.idx
       c.add(a)
       c.add(b)
       c.order = order; inc order
@@ -2262,6 +2262,8 @@ proc parseDefinitionList(p: var RstParser): PRstNode =
     var col = currentTok(p).col
     result = newRstNodeA(p, rnDefList)
     while true:
+      if isOptionList(p):
+        break  # option list has priority over def.list
       j = p.idx
       var a = newRstNode(rnDefName)
       parseLine(p, a)

tests/stdlib/trst.nim

@@ -83,6 +83,53 @@ suite "RST parsing":
               rnLeaf  'set'
         """)
 
+  test "items of 1 option list can be separated by blank lines":
+    check(dedent"""
+        -a  desc1
+
+        -b  desc2
+        """.toAst ==
+      dedent"""
+        rnOptionList
+          rnOptionListItem  order=1
+            rnOptionGroup
+              rnLeaf  '-'
+              rnLeaf  'a'
+            rnDescription
+              rnLeaf  'desc1'
+          rnOptionListItem  order=2
+            rnOptionGroup
+              rnLeaf  '-'
+              rnLeaf  'b'
+            rnDescription
+              rnLeaf  'desc2'
+      """)
+
+  test "option list has priority over definition list":
+    check(dedent"""
+        defName
+            defBody
+
+        -b  desc2
+        """.toAst ==
+      dedent"""
+        rnInner
+          rnDefList
+            rnDefItem
+              rnDefName
+                rnLeaf  'defName'
+              rnDefBody
+                rnInner
+                  rnLeaf  'defBody'
+          rnOptionList
+            rnOptionListItem  order=1
+              rnOptionGroup
+                rnLeaf  '-'
+                rnLeaf  'b'
+              rnDescription
+                rnLeaf  'desc2'
+      """)
+
   test "RST comment":
     check(dedent"""
         .. comment1