Pin the mark run and a line break's whitespace edges

corpus/round-trip/inline-nodes/marks.json

@@ -11,7 +11,19 @@
               "type": "textColor"
             }
           ],
-          "text": "Overdue",
+          "text": "Over",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "attrs": {
+                "color": "#a54800"
+              },
+              "type": "textColor"
+            }
+          ],
+          "text": "due",
           "type": "text"
         },
         {
@@ -40,9 +52,21 @@
               "type": "underline"
             }
           ],
-          "text": "signed",
+          "text": "signed by ",
           "type": "text"
         },
+        {
+          "attrs": {
+            "id": "01a032c3-7a7c-775f-a730-2d79351338b4",
+            "text": "@Mikael"
+          },
+          "marks": [
+            {
+              "type": "underline"
+            }
+          ],
+          "type": "mention"
+        },
         {
           "text": " on the 2",
           "type": "text"

corpus/round-trip/inline-nodes/marks.md

@@ -1,3 +1,3 @@
-:textColor[Overdue]{color="#ae2e24"} since the H:subsup[2]{type=sub}O test, :underline[signed] on the 2:subsup[nd]{type=sup} of May.
+:textColor[Over]{color="#ae2e24"}:textColor[due]{color="#a54800"} since the H:subsup[2]{type=sub}O test, :underline[signed by :mention[@Mikael]{id=01a032c3-7a7c-775f-a730-2d79351338b4}] on the 2:subsup[nd]{type=sup} of May.
 
 :border[:mediaInline{collection=contentId-98237 id=01a032c3-7a90-70c9-88f6-c60f710eda07}]{color="#091e42" size=2}

corpus/round-trip/inline-nodes/text-whitespace.json

@@ -27,6 +27,38 @@
       ],
       "type": "paragraph"
     },
+    {
+      "content": [
+        {
+          "text": "Space before the break ",
+          "type": "text"
+        },
+        {
+          "type": "hardBreak"
+        },
+        {
+          "text": "survives.",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "text": "Space after the break",
+          "type": "text"
+        },
+        {
+          "type": "hardBreak"
+        },
+        {
+          "text": " survives too.",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
     {
       "content": [
         {

corpus/round-trip/inline-nodes/text-whitespace.md

@@ -4,4 +4,10 @@ Trailing space held:text{text=" "}
 
 :text{text="\t"}Tabbed at the block edge.
 
+Space before the break:text{text=" "}\
+survives.
+
+Space after the break\
+:text{text=" "}survives too.
+
 Kept _:text{text=" "}inside:text{text=" "}_, exactly.