feat: Add zed-comment support for all ERB languages (#205)

Similar to #203, this adds
[`zed-comment`](https://github.com/thedadams/zed-comment) support for
all `ERB` languages.

<img width="862" height="570" alt="CleanShot 2025-11-08 at 17 41 28@2x"
src="https://github.com/user-attachments/assets/833dc324-70ab-424a-991c-cadd6cd0eb14"
/>

Author: marcoroth

languages/erb/injections.scm

@@ -5,3 +5,7 @@
 ((content) @content
   (#set! "language" "plaintext")
   (#set! "combined"))
+
+((comment) @content
+  (#set! injection.language "comment")
+  (#set! "combined"))

languages/html-erb/injections.scm

@@ -5,3 +5,7 @@
 ((content) @content
   (#set! "language" "html")
   (#set! "combined"))
+
+((comment) @content
+  (#set! injection.language "comment")
+  (#set! "combined"))

languages/js-erb/injections.scm

@@ -5,3 +5,7 @@
 ((content) @content
   (#set! "language" "javascript")
   (#set! "combined"))
+
+((comment) @content
+  (#set! injection.language "comment")
+  (#set! "combined"))

languages/yaml-erb/injections.scm

@@ -5,3 +5,7 @@
 ((content) @content
   (#set! "language" "yaml")
   (#set! "combined"))
+
+((comment) @content
+  (#set! injection.language "comment")
+  (#set! "combined"))