chore: added code format for zod example in docs

Author: david-roper

docs/en/5-reference/5.0-form-instrument.md

@@ -55,12 +55,12 @@ Always consider using \`group\`ing to structure sections
    - Make sure your rules are correct given the paper form
    - Please familiarize yourself with the possible validation rules here
    - Be careful to write the most restrictive validation schema possible
-     - Example: likert-scale data should be .int()
-     - Example: A select from multiple string options question should be .enum(['option1','option2', ...]) instead of .string()
+     - Example: likert-scale data should be `.int()`
+     - Example: A select from multiple string options question should be `.enum(['option1','option2', ...])` instead of `.string()`
      - Remember the API data-entry is independent of the form, so the validation schema must properly restrict API entry as well
 5. Please make sure to format your code whenever possible, as this can prevent annoying issues with missing brackets. In the playground, you can do this with (Alt + F)
 6. If you find yourself repeating code frequently, consider extracting the logic into shared variables. The guiding principle of this should be to maximize readability.
-   - For example, if your data schema is z.number().int().min(0).max(7) for every field, consider moving it into a variable, as this can reduce the cognitive load of programmers reading your form
+   - For example, if your data schema is `z.number().int().min(0).max(7)` for every field, consider moving it into a variable, as this can reduce the cognitive load of programmers reading your form
    - On the other hand, if this is the schema for only two or three variables, creating a variable would probably increase cognitive load, rather than reducing it.
    - The same applies for computed measures (i.e., define a function at the top of your file instead of copy-pasting it to every field).
 7. Review common styling conventions
@@ -70,7 +70,7 @@ Always consider using \`group\`ing to structure sections
    - It is setup with formatting, linting, and type checking by default
 9. Proper use of Zod's enum type
    - It is best to use Zod's enum type when the answer to a form question is a set of constant values.
-   - Example: A question which asks the user to choose from a selection of options should use z.enum([option1, option2, ...]) within its zod validation schema.
+   - Example: A question which asks the user to choose from a selection of options should use `z.enum([option1, option2, ...])` within its zod validation schema.
 
 ### Example