Fix "have a PR merged" heading links (#439)

Author: jennaswa

_posts/2025-02-28-gsoc2025.md

@@ -66,7 +66,7 @@ In short:
 1. [Agree to be bound by our Code of Conduct](#code-of-conduct) (and [WESTPA's Code of Conduct](https://github.com/westpa/westpa/wiki/Code-of-Conduct) if you are applying for a WESTPA collaboration project [i.e., [Project 1]({{ site.github.wiki }}/GSoC-2025-Project-Ideas#project-1-integrating-mdanalysis-streaming-analysis-within-westpa-propagators), [Project 2]({{ site.github.wiki }}/GSoC-2025-Project-Ideas#project-2-dashboard-for-tracking-westpa-simulation-progress)]);
 2. [Familiarize yourself with MDAnalysis and relevant partner projects](#familiarize-yourself-with-mdanalysis-and-relevant-partner-projects);
 3. [Submit a short pre-proposal](#submit-a-pre-proposal) — 
-4. **If you have been invited to proceed with your application (based on your pre-proposal)** [have a pull request merged](#have-a-pull-request-merged-if-you-are-invited-to-based-on-your-pre-proposal) in MDAnalysis or a partner organization.
+4. **If you have been invited to proceed with your application (based on your pre-proposal)** [have a pull request merged](#have-a-pull-request-merged-by-invitation) in MDAnalysis or a partner organization.
 
 ### Code of Conduct
 
@@ -109,7 +109,7 @@ As some of the [project ideas][ideas] represent collaboration between MDAnalysis
 
 We ask you to submit a short *pre-proposal* so that we can evaluate your understanding of the proposed project. In this pre-proposal you tell us what project you’d like to work on, what you consider the major challenges, and how you plan to solve the problem. MDAnalysis developers will review your proposal and then either invite you to continue with your application and work on an issue to get involved in the code development or tell you that we will not consider your application. *Please note that this decision is final, and applicants should only submit **one** pre-proposal.* A rejection is not a judgment on you or your abilities but an assessment of how well you fit the specific requirements of MDAnalysis as a scientific software package — we much rather you spend your energies on contributing to another exciting GSoC project than being rejected later by MDAnalysis. 
 
-**We require GSoC applicants to submit a pre-proposal** that will determine who is then invited to [contribute a pull request for evaluation](#have-a-pull-request-merged-if-you-are-invited-to-based-on-your-pre-proposal) (see below). If you are invited to contribute a pull request and ultimately submit a full application, the pre-proposal will help you gather some of the information you will need to include. 
+**We require GSoC applicants to submit a pre-proposal** that will determine who is then invited to [contribute a pull request for evaluation](#have-a-pull-request-merged-by-invitation) (see below). If you are invited to contribute a pull request and ultimately submit a full application, the pre-proposal will help you gather some of the information you will need to include. 
 
 Submit your pre-proposal via [this submission form][submission form] **as soon as possible, but no later than March 21, 2025**. You should prepare the following information for your pre-proposal:
 * Email address