.github: try "import/path: issue title" instead of "affected/package: "

The multiple issue templates pre-populate the issue title with a prefix
that Go issues customarily have. The "affected/package" phrase is short
for "the import path of the affected package". Let's try simplifying it
to just "import/path", and also include "issue title" to make the title
a more representative template of what the final title should look like.

Updates #29839.

Change-Id: I9736d24cf3d0a51536ac13dd07dd189fb51da021
Reviewed-on: https://go-review.googlesource.com/c/go/+/544556
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Sean Liao <sean@liao.dev>

.github/ISSUE_TEMPLATE/00-bug.yml

@@ -3,7 +3,7 @@
 name: Bugs
 description: The go command, standard library, or anything else
 labels: [ 'kind/bug', 'bug' ]
-title: "affected/package: "
+title: "import/path: issue title"
 
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/01-pkgsite.yml

@@ -1,6 +1,6 @@
 name: Pkg.go.dev bugs or feature requests
 description: Issues or feature requests for the documentation site
-title: "x/pkgsite: "
+title: "x/pkgsite: issue title"
 labels: ["pkgsite"]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/03-gopls.yml

@@ -1,6 +1,6 @@
 name: Gopls bugs or feature requests
 description: Issues or feature requests for the Go language server (gopls)
-title: "x/tools/gopls: "
+title: "x/tools/gopls: issue title"
 labels: ["gopls", "Tools"]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/04-vuln.yml

@@ -1,6 +1,6 @@
 name: Go vulnerability management - bugs and feature requests
 description: Issues or feature requests about Go vulnerability management
-title: "x/vuln: "
+title: "x/vuln: issue title"
 labels: ["vulncheck", "vulndb"]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/10-proposal.yml

@@ -1,6 +1,6 @@
 name: Proposals
 description: New external API or other notable changes
-title: "proposal: affected/package: "
+title: "proposal: import/path: proposal title"
 labels: ["Proposal"]
 body:
   - type: markdown

.github/ISSUE_TEMPLATE/11-language-change.yml

@@ -1,7 +1,7 @@
 name: Language Change Proposals
 description: Changes to the language
 labels: ["Proposal", "v2", "LanguageChange"]
-title: "proposal: Go 2: "
+title: "proposal: Go 2: proposal title"
 
 
 body:

.github/ISSUE_TEMPLATE/12-telemetry.yml

@@ -1,6 +1,6 @@
 name: Go Telemetry Proposals
 description: New telemetry counter or update on an existing one
-title: "x/telemetry/config: "
+title: "x/telemetry/config: issue title"
 labels: ["Telemetry-Proposal"]
 projects: ["golang/29"]
 body: