Fix ~219 spelling mistakes across documentation and source code comments

Fix ~219 spelling mistakes across 92 files in documentation (.rst, .md),
source code comments/docstrings, and CI/build scripts.

Identified using **codespell v2.4.1** with a custom ignore list for
project-specific terms, followed by manual review to avoid false positives.

**Examples of corrections:**

| Original | Corrected | Location |
|----------|-----------|----------|
| `compabitility` | `compatibility` | README.rst |
| `environement` | `environment` | multiple files |
| `comparision` | `comparison` | docs/ |
| `maintainence` | `maintenance` | CHANGELOG.rst |
| `dependecy` | `dependency` | CHANGELOG.rst |
| `mispelled` | `misspelled` | copyrights.py |
| `ambigious` | `ambiguous` | multiple files |
| `simultaniously` | `simultaneously` | docs/ |
| `boostrapping` | `bootstrapping` | etc/scripts/ |
| `cheksums` | `checksums` | golang.py + test fixtures |

**What is NOT changed:**
- No code logic, variable names, function names, or class names
- No URLs, file paths, or domain names
- No license rule files (`*.RULE`), test data, or third-party code
- Intentional non-standard spellings preserved (e.g., `exmaple.com` junk filter in `finder_data.py`)

**Note:** Small overlap with #4712 which also fixes `compabitility` in README.rst.

### Link to Documentation Page

Affects multiple documentation pages including:
- https://scancode-toolkit.readthedocs.io/en/stable/getting-started/contribute/contributing-code.html
- https://scancode-toolkit.readthedocs.io/en/stable/getting-started/contribute/contributing-docs.html
- https://scancode-toolkit.readthedocs.io/en/stable/reference/scancode-cli/cli-basic-options.html
- https://scancode-toolkit.readthedocs.io/en/stable/explanation/scancode-license-detection-updates.html
- And 18+ other documentation pages, plus source code comments in `src/`

### Select Category

- [ ] Inconsistency
- [ ] New Section Request
- [ ] General Improvement
- [x] Typo/Mistakes
- [ ] Other

Signed-off-by: Mrityunjay Raj