docs: adding false positives to mismatch data (#4245)

Signed-off-by: Meet Soni <meetsoni3017@gmail.com>

.github/actions/spelling/allow.txt

@@ -177,6 +177,7 @@ exploitability
 Exploitablity
 f
 faad
+facebook
 fastd
 fde
 fedora
@@ -433,6 +434,7 @@ mysql
 Mystylesheet
 MYUSERNAME
 namespaces
+namespace
 nano
 nasm
 nbd

data/pypi/zstandard/mismatch_relations.yml

@@ -0,0 +1,4 @@
+purls:
+  - pkg:pypi/zstandard
+invalid_vendors:
+  - facebook

doc/index.rst

@@ -24,6 +24,7 @@ The CVE Binary Tool helps you determine if your system includes known vulnerabil
    sboms_for_humans/README.md
    new-contributor-tips.md
    pypi_downloads.md
+   mismatch_data.md
 
 Indices and tables
 ==================

doc/mismatch_data.md

@@ -0,0 +1,47 @@
+# Adding data to mismatch database
+
+CVE Binary Tool uses a number of sources for vulnerability and risk data. Sometimes these can produce name collision, and to tackle this we've created a `mismatch` 
+database.
+
+This document details the steps for adding data to the mismatch database.
+
+## 1. Update `data/` directory
+
+1. Make a new file with `namespace/product_name/mismatch_relations.yml` name under the `data/` directory. For example, `pypi/zstandard/mismatch_relations.yml` for zstandard
+from pypi namespace.
+2. Populate the file with `purl-invalid_vendor` information.
+
+```yml
+  purls:
+    - pkg:pypi/zstandard
+  invalid_vendors:
+    - facebook
+```
+
+## 2. Run the populator script
+
+The [`mismatch_loader`](../cve_bin_tool/mismatch_loader.py) script populates the the mismatch database with the contents of `data/` directory.
+
+```python
+    python -m cve_bin_tool.mismatch_loader
+```
+
+The default directory is `data/`, and default database file is `cve.db`.
+
+To use a specific directory, use `--dir` flag:
+```python
+    python -m cve_bin_tool.mismatch_loader --dir directory_location
+```
+
+To use a specific database file, use `--database` flag:
+```python
+    python -m cve_bin_tool.mismatch_loader --database database_file_location
+```
+
+## 3. (optional) Make pull request of new-found name collision
+
+If you find invalid relationship, please do following:
+
+- Fork the [repo](https://github.com/intel/cve-bin-tool)
+- Update the `data/` directory with purl-invalid_vendor information like [this](../data/pypi/zstandard/mismatch_relations.yml)
+- Create a pull request with the details of update. [Reference](https://github.com/intel/cve-bin-tool/pull/4239)