Update list for one file type in supported-file-types-platform.mdx (#633)

Author: Paul-Cornell

snippets/general-shared-text/supported-file-types-platform.mdx

@@ -45,7 +45,6 @@ By file extension:
 | `.txt` |
 | `.tsv` |
 | `.xls` |
-| `.xlsm` |
 | `.xlsx` |
 | `.xml` |
 | `.zabw` |
@@ -68,7 +67,7 @@ By file type:
 | PowerPoint | `.pot`, `.ppt`, `.pptm`, `.pptx` |
 | reStructured Text | `.rst` |
 | Rich Text | `.rtf` |
-| Spreadsheet | `.et`, `.xls`, `.xlsm`, `.xlsx` |
+| Spreadsheet | `.et`, `.xls`, `.xlsx` |
 | StarOffice | `.sxg` |
 | TSV | `.tsv` |
 | Word processing | `.abw`, `.doc`, `.docx`, `.dot`, `.hwp`, `.zabw` |
@@ -77,4 +76,4 @@ By file type:
 ## Notes
 
 * For `.dif`, `\n` characters in `.dif` files are supported, but `\r\n` characters will raise the error 
-  `UnsupportedFileFormatError: Partitioning is not supported for the FileType.UNK file type`.
+  `UnsupportedFileFormatError: Partitioning is not supported for the FileType.UNK file type`.