docs: fix documentation typo in Page.waitForSelector optional visible parameter (#9381)

**What kind of change does this PR introduce?**

Typo fix in the documentation

**Did you add tests for your changes?**

No

**If relevant, did you update the documentation?**

N/A

**Summary**

I spotted the `Visible` parameter had an uppercase `V` in the [Remarks
section of the Page.waitForSelector API
documentation](https://pptr.dev/api/puppeteer.page.waitforselector#remarks).
Updated this to the lowercase `v` in the relevant places (source,
documentation, versioned version of the doc page).

While doing this, I also spotted there was an extra space in `are :` in
the sentence above – so changed that as well.

**Does this PR introduce a breaking change?**

No

**Other information**

I’ve confirmed the parameter is spelled correctly on
https://pptr.dev/api/puppeteer.waitforselectoroptions. I’m not sure why
the documentation for those properties is in two places with slightly
different wording – but to me it felt useful to see this directly on the
method’s API docs.

docs/api/puppeteer.page.waitforselector.md

@@ -56,7 +56,7 @@ Promise which resolves when element specified by selector string is added to DOM
 
 The optional Parameter in Arguments `options` are:
 
-- `Visible`: A boolean wait for element to be present in DOM and to be visible, i.e. to not have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.
+- `visible`: A boolean wait for element to be present in DOM and to be visible, i.e. to not have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.
 
 - `hidden`: Wait for element to not be found in the DOM or to be hidden, i.e. have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.
 

packages/puppeteer-core/src/api/Page.ts

@@ -2400,7 +2400,7 @@ export class Page extends EventEmitter {
    * @remarks
    * The optional Parameter in Arguments `options` are:
    *
-   * - `Visible`: A boolean wait for element to be present in DOM and to be
+   * - `visible`: A boolean wait for element to be present in DOM and to be
    *   visible, i.e. to not have `display: none` or `visibility: hidden` CSS
    *   properties. Defaults to `false`.
    *

website/versioned_docs/version-19.4.0/api/puppeteer.page.waitforselector.md

@@ -56,7 +56,7 @@ Promise which resolves when element specified by selector string is added to DOM
 
 The optional Parameter in Arguments `options` are:
 
-- `Visible`: A boolean wait for element to be present in DOM and to be visible, i.e. to not have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.
+- `visible`: A boolean wait for element to be present in DOM and to be visible, i.e. to not have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.
 
 - `hidden`: Wait for element to not be found in the DOM or to be hidden, i.e. have `display: none` or `visibility: hidden` CSS properties. Defaults to `false`.