docs: fix typo in develop.md (#26510)

Correct a subject-verb agreement error ("is" to "are") in the develop.md
documentation file.

Signed-off-by: Viktor Dovhoshyia <mr.dovgoshiya@gmail.com>

content/reference/compose-file/develop.md

@@ -97,7 +97,7 @@ The syntax is the same as `.dockerignore` file:
 - `*/*` matches two nested folders with arbitrary names
 - `**` matches an arbitrary number of nested folders
 
-If the build context includes a `.dockerignore` file, the patterns in this file is loaded as implicit content
+If the build context includes a `.dockerignore` file, the patterns in this file are loaded as implicit content
 for the `ignores` file, and values set in the Compose model are appended.
 
 #### `include`