fix missing docstrings in module

Author: zth

analysis/src/DocExtraction.ml

@@ -156,6 +156,7 @@ let rec stringifyDocItem ?(indentation = 0) ~originalEnv (item : docItem) =
         ("id", Some (wrapInQuotes m.id));
         ("name", Some (wrapInQuotes m.name));
         ("kind", Some (wrapInQuotes "module"));
+        ("docstrings", Some (stringifyDocstrings m.docstring));
         ( "items",
           Some
             (m.items

analysis/tests/src/expected/DocExtraction2.res.txt

@@ -24,6 +24,7 @@ preferring found resi file for impl: src/DocExtraction2.resi
     "id": "DocExtraction2.InnerModule",
     "name": "InnerModule",
     "kind": "module",
+    "docstrings": [],
     "items": [
     {
       "id": "DocExtraction2.InnerModule.t",

analysis/tests/src/expected/DocExtraction2.resi.txt

@@ -23,6 +23,7 @@ extracting docs for src/DocExtraction2.resi
     "id": "DocExtraction2.InnerModule",
     "name": "InnerModule",
     "kind": "module",
+    "docstrings": [],
     "items": [
     {
       "id": "DocExtraction2.InnerModule.t",

analysis/tests/src/expected/DocExtractionRes.res.txt

@@ -45,6 +45,7 @@ extracting docs for src/DocExtractionRes.res
     "id": "DocExtractionRes.SomeInnerModule",
     "name": "SomeInnerModule",
     "kind": "module",
+    "docstrings": ["Another module level docstring here."],
     "items": [
     {
       "id": "DocExtractionRes.SomeInnerModule.status",
@@ -92,6 +93,7 @@ extracting docs for src/DocExtractionRes.res
     "id": "DocExtractionRes.AnotherModule",
     "name": "AnotherModule",
     "kind": "module",
+    "docstrings": ["Mighty fine module here too!"],
     "items": [
     {
       "id": "DocExtractionRes.LinkedModule",
@@ -154,6 +156,7 @@ extracting docs for src/DocExtractionRes.res
     "id": "DocExtractionRes.ModuleWithThingsThatShouldNotBeExported",
     "name": "ModuleWithThingsThatShouldNotBeExported",
     "kind": "module",
+    "docstrings": [],
     "items": [
     {
       "id": "DocExtractionRes.ModuleWithThingsThatShouldNotBeExported.t",