Confirmation prompt when clearing a workspace should never show "Delete all 1 blocks". Either never show a confirmation if the workspace only has one block (Blockly style), or use the DELETE_BLOCK message template ("Delete Block").

Any.
Workspace context menu option: https://github.com/LLK/scratch-blocks/blob/develop/core/workspace_svg.js#L1460
Block context menu option: https://github.com/LLK/scratch-blocks/blob/develop/core/block_svg.js#L772
We should fix this for English, but it's not really going to help the person who filed the blockly issue. They're translating to Scottish Gaelic, which has 4 plural forms (one, two, few, other) instead of 2 like English (and the 'one' form applies to 1 and 11 to complicate things further). So for them, 'Delete all 3 blocks' should be translated differently from 'Delete all 20 blocks'
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We should fix this for English, but it's not really going to help the person who filed the blockly issue. They're translating to Scottish Gaelic, which has 4 plural forms (one, two, few, other) instead of 2 like English (and the 'one' form applies to 1 and 11 to complicate things further). So for them, 'Delete all 3 blocks' should be translated differently from 'Delete all 20 blocks'