pr-base-commit does not append a trailing whitespace to the injected message when needed

[DanielMiao1]

Description

The code for the pr-base-commit feature that injects the "x commits behind (base commit: 1234567)" message in the addInfo function does not currently account for an Only those with write access ... can merge pull requests message, causing a missing whitespace character before the word "Only" (see figure 1).

How to replicate the issue + URL

1. Navigate to an open, non-draft, and non-blocked pull request behind the base branch that you do not have permission to merge (in order to display the write-access message) such as update sitemap for commit 79b76c6 DanielMiao1/test#6
2. Observe the issue:
    

Figure 1

Extension version

23.5.10

Browser(s) used

all supported browsers

[fregante]

Thank you, one issue is enough: #6650