splice: Add documentation for splicein

diff --git a/contrib/msggen/msggen/schema.json b/contrib/msggen/msggen/schema.json
index 808fbc3e..36e2ba81 100644
--- a/contrib/msggen/msggen/schema.json
+++ b/contrib/msggen/msggen/schema.json
@@ -34045,6 +34045,73 @@
         }
       ]
     },
+    "splicein.json": {
+      "$schema": "../rpc-schema-draft.json",
+      "type": "object",
+      "additionalProperties": false,
+      "added": "v26.04",
+      "rpc": "splicein",
+      "title": "Command to splice funds into a channel",
+      "warning": "experimental-splicing only",
+      "description": [
+        "`splicein` is the command to move funds into a channel."
+      ],
+      "request": {
+        "required": [
+          "channel",
+          "amount"
+        ],
+        "properties": {
+          "channel": {
+            "type": "string",
+            "description": [
+              "channel identifier or channel query. Format is the same as is used in `dev-splice`."
+            ]
+          },
+          "amount": {
+            "type": "string",
+            "description": [
+              "Amount in satoshis taken from the internal wallet and add to the channel. Format is the same as is used in `dev-splice`."
+            ]
+          }
+        }
+      },
+      "response": {
+        "required": [],
+        "properties": {
+          "psbt": {
+            "type": "string",
+            "description": [
+              "The final psbt"
+            ]
+          },
+          "tx": {
+            "type": "string",
+            "description": [
+              "The final transaction in hex"
+            ]
+          },
+          "txid": {
+            "type": "string",
+            "description": [
+              "The txid of the final transaction"
+            ]
+          }
+        }
+      },
+      "usage": [
+        "`splicein` is the command to add funds to a channel. It takes `amount` funds from your onchain wallet and places them into `channel`."
+      ],
+      "author": [
+        "Dusty [@dusty_daemon](mailto:@dustydaemon) is mainly responsible."
+      ],
+      "see_also": [
+        "lightning-dev-splice(7)"
+      ],
+      "resources": [
+        "Main web site: [https://github.com/ElementsProject/lightning](https://github.com/ElementsProject/lightning)"
+      ]
+    },
     "sql-template.json": {
       "$schema": "../rpc-schema-draft.json",
       "type": "object",
diff --git a/doc/Makefile b/doc/Makefile
index e99c3ded..8fa6fa49 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -135,6 +135,7 @@ MARKDOWNPAGES := doc/addgossip.7 \
 	doc/signmessage.7 \
 	doc/signmessagewithkey.7 \
 	doc/signpsbt.7 \
+	doc/splicein.7 \
 	doc/splice_init.7 \
 	doc/splice_signed.7 \
 	doc/splice_update.7 \
diff --git a/doc/index.rst b/doc/index.rst
index 3a495cfe..dcc2ea10 100644
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -154,6 +154,7 @@ Core Lightning Documentation
    splice_init <splice_init.7.md>
    splice_signed <splice_signed.7.md>
    splice_update <splice_update.7.md>
+   splicein <splicein.7.md>
    sql <sql.7.md>
    staticbackup <staticbackup.7.md>
    stop <stop.7.md>
diff --git a/doc/schemas/splicein.json b/doc/schemas/splicein.json
new file mode 100644
index 00000000..df3166d0
--- /dev/null
+++ b/doc/schemas/splicein.json
@@ -0,0 +1,67 @@
+{
+  "$schema": "../rpc-schema-draft.json",
+  "type": "object",
+  "additionalProperties": false,
+  "added": "v26.04",
+  "rpc": "splicein",
+  "title": "Command to splice funds into a channel",
+  "warning": "experimental-splicing only",
+  "description": [
+    "`splicein` is the command to move funds into a channel."
+  ],
+  "request": {
+    "required": [
+      "channel",
+      "amount"
+    ],
+    "properties": {
+      "channel": {
+        "type": "string",
+        "description": [
+          "channel identifier or channel query. Format is the same as is used in `dev-splice`."
+        ]
+      },
+      "amount": {
+        "type": "string",
+        "description": [
+          "Amount in satoshis taken from the internal wallet and add to the channel. Format is the same as is used in `dev-splice`."
+        ]
+      }
+    }
+  },
+  "response": {
+    "required": [],
+    "properties": {
+      "psbt": {
+        "type": "string",
+        "description": [
+          "The final psbt"
+        ]
+      },
+      "tx": {
+        "type": "string",
+        "description": [
+          "The final transaction in hex"
+        ]
+      },
+      "txid": {
+        "type": "string",
+        "description": [
+          "The txid of the final transaction"
+        ]
+      }
+    }
+  },
+  "usage": [
+    "`splicein` is the command to add funds to a channel. It takes `amount` funds from your onchain wallet and places them into `channel`."
+  ],
+  "author": [
+    "Dusty [@dusty_daemon](mailto:@dustydaemon) is mainly responsible."
+  ],
+  "see_also": [
+    "lightning-dev-splice(7)"
+  ],
+  "resources": [
+    "Main web site: [https://github.com/ElementsProject/lightning](https://github.com/ElementsProject/lightning)"
+  ]
+}