[bugfix] Remove errant `alsoKnownAs` inline `@context` entry (#4280)

# Description

> If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.
>
> If this is a documentation change, please briefly describe what you've changed and why.

Our extra `alsoKnownAs` inline `@context` entry was incorrect, and doesn't need to be included anyways as it's already present at the AS namespace context doc here: https://www.w3.org/ns/activitystreams. This PR just removes it :)

closes https://codeberg.org/superseriousbusiness/gotosocial/issues/3883

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [ ] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4280
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

5 files changed, 4 insertions, 6 deletions

diff --git a/go.mod b/go.mod
index 745378afe..d440a19b7 100644
--- a/go.mod
+++ b/go.mod
@@ -11,7 +11,7 @@ replace github.com/go-swagger/go-swagger => codeberg.org/superseriousbusiness/go
 replace modernc.org/sqlite => gitlab.com/NyaaaWhatsUpDoc/sqlite v1.38.0-concurrency-workaround
 
 require (
-	code.superseriousbusiness.org/activity v1.15.0
+	code.superseriousbusiness.org/activity v1.15.1
 	code.superseriousbusiness.org/exif-terminator v0.11.0
 	code.superseriousbusiness.org/httpsig v1.4.0
 	code.superseriousbusiness.org/oauth2/v4 v4.5.4-0.20250606121655-9d54ef189d42
diff --git a/go.sum b/go.sum
index f03fce7d8..371c10d62 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-code.superseriousbusiness.org/activity v1.15.0 h1:XwdO/1ssry8GCLWDFlUxSb+lNpUvdjkKG3HVHTEkvi4=
-code.superseriousbusiness.org/activity v1.15.0/go.mod h1:BTMWJIAuwDH1w+ieRP5N+T5LipbXjw35U6KZy0V/xdg=
+code.superseriousbusiness.org/activity v1.15.1 h1:vCJ4X8wscBWnrBh61Reot64p8LZmlyoFfj7qjcci840=
+code.superseriousbusiness.org/activity v1.15.1/go.mod h1:BTMWJIAuwDH1w+ieRP5N+T5LipbXjw35U6KZy0V/xdg=
 code.superseriousbusiness.org/exif-terminator v0.11.0 h1:Hof0MCcsa+1fS17gf86fTTZ8AQnMY9h9kzcc+2C6mVg=
 code.superseriousbusiness.org/exif-terminator v0.11.0/go.mod h1:9sutT1axa/kSdlPLlRFjCNKmyo/KNx8eX3XZvWBlAEY=
 code.superseriousbusiness.org/go-jpeg-image-structure/v2 v2.3.0 h1:r9uq8StaSHYKJ8DklR9Xy+E9c40G1Z8yj5TRGi8L6+4=
diff --git a/internal/typeutils/internaltoas_test.go b/internal/typeutils/internaltoas_test.go
index 292d7705a..5da103582 100644
--- a/internal/typeutils/internaltoas_test.go
+++ b/internal/typeutils/internaltoas_test.go
@@ -259,7 +259,6 @@ func (suite *InternalToASTestSuite) TestAccountToASAliasedAndMoved() {
     "https://w3id.org/security/v1",
     "https://www.w3.org/ns/activitystreams",
     {
-      "alsoKnownAs": "as:alsoKnownAs",
       "discoverable": "toot:discoverable",
       "featured": {
         "@id": "toot:featured",
diff --git a/vendor/code.superseriousbusiness.org/activity/streams/util.go b/vendor/code.superseriousbusiness.org/activity/streams/util.go
index def40c6ec..b2f2ff679 100644
--- a/vendor/code.superseriousbusiness.org/activity/streams/util.go
+++ b/vendor/code.superseriousbusiness.org/activity/streams/util.go
@@ -23,7 +23,6 @@ const (
 // when vocabs include "https://www.w3.org/ns/activitystreams".
 var asInlines = map[string]any{
 	"Hashtag":                   "as:Hashtag",
-	"alsoKnownAs":               "as:alsoKnownAs",
 	"manuallyApprovesFollowers": "as:manuallyApprovesFollowers",
 	"sensitive":                 "as:sensitive",
 
diff --git a/vendor/modules.txt b/vendor/modules.txt
index cca8b4d64..ff5c0000f 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -1,4 +1,4 @@
-# code.superseriousbusiness.org/activity v1.15.0
+# code.superseriousbusiness.org/activity v1.15.1
 ## explicit; go 1.23
 code.superseriousbusiness.org/activity/pub
 code.superseriousbusiness.org/activity/streams