[docs] fix docs snippet and markdown content

[jjyeo]

Summary & Motivation

1. Add a code snippet for Backfill processing configuration in dagster.yaml.
   

2. Remove Location of workspace.yaml section from workspace-yaml.md as it duplicates the Loading workspace files section.

3. Fix Markdown table under Job execution flow.
   

Test Plan

Local build and test

[greptile-apps]

Greptile Summary

This PR makes several targeted documentation fixes across the Dagster OSS docs: adds the missing backfills YAML snippet to dagster.yaml (filling a pre-existing <CodeExample> reference in oss-instance-configuration.md), fixes a broken Markdown table in the deployment architecture page, corrects a formatting issue in the Docker Compose prerequisites callout, removes a duplicated section from workspace-yaml.md, and fixes a double-word typo in the tutorial.

• dagster.yaml: New backfills snippet (use_threads, num_workers) is correctly keyed per the Dagster source (backfills_daemon_config()), and its markers (start_marker_backfills/end_marker_backfills) are already expected by the <CodeExample> in oss-instance-configuration.md.
• oss-deployment-architecture.md: The "Job execution flow" table now has a proper numeric Order column and correctly-aligned Component/Description/Configured-by columns.
• docker.md: Prerequisites list items were previously collapsed onto a single line; now correctly formatted as separate Markdown list items.
• workspace-yaml.md: The standalone "Location of workspace.yaml" section (including the -w flag example) was entirely duplicated by the existing "Loading workspace files" section and has been removed.
• 6-custom-components.md: Minor typo fix ("a a YAML" → "a YAML").

Confidence Score: 5/5

• This PR is safe to merge — all changes are documentation-only fixes with no runtime code impact.
• All five changes are pure documentation fixes (formatting, typo, duplicate removal, and a YAML snippet addition). The new backfill config keys are verified correct against the Dagster source. No behavioral code is touched.
• No files require special attention.

Important Files Changed

Filename	Overview
examples/docs_snippets/docs_snippets/deploying/dagster_instance/dagster.yaml	Adds a backfills YAML snippet between start_marker_backfills/end_marker_backfills markers, which are already referenced by the <CodeExample> in oss-instance-configuration.md. The use_threads and num_workers keys are confirmed correct per the Dagster source (backfills_daemon_config()). Consistent pattern with existing sensors and schedules snippets.
docs/docs/deployment/oss/oss-deployment-architecture.md	Fixes a broken Markdown table for "Job execution flow" — adds a proper numeric Order column (1–4) and correctly distributes component links, descriptions, and config-level values across the right columns.
docs/docs/deployment/oss/deployment-options/docker.md	Fixes collapsed prerequisites in the <details> block — separates the previously concatenated list items onto their own lines for correct Markdown rendering.
docs/docs/guides/build/projects/workspaces/workspace-yaml.md	Removes the duplicate "Location of workspace.yaml" section; the same content (including the -w flag usage) is already fully covered in the "Loading workspace files" section below.
docs/docs/dagster-basics-tutorial/6-custom-components.md	Fixes a double-word typo: "from a a YAML" → "from a YAML".

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["dagster.yaml snippet file\n(docs_snippets/deploying/dagster_instance/dagster.yaml)"]

    A -->|start_marker_backfills / end_marker_backfills| B["oss-instance-configuration.md\n(Backfill processing section)"]
    A -->|start_marker_schedules / end_marker_schedules| C["oss-instance-configuration.md\n(Schedule processing section)"]
    A -->|start_marker_sensors / end_marker_sensors| D["oss-instance-configuration.md\n(Sensor processing section)"]

    B --> E["Rendered Docs Page:\nBackfill Processing Config Example"]

    subgraph "Other Docs Fixes (this PR)"
        F["oss-deployment-architecture.md\nFixed Job Execution Flow table"]
        G["docker.md\nFixed Prerequisites formatting"]
        H["workspace-yaml.md\nRemoved duplicate section"]
        I["6-custom-components.md\nFixed double-word typo"]
    end

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_{Last reviewed commit: 9edbbd5}

[neverett]

@jjyeo There have been some changes to master since you opened this, can you rebase? Thanks!

[jjyeo]

@neverett Changes applied. Could you please review it? Thank you.