popup tooltip on image in browser ends on first word

In such constructions the tooltip will only show "Some":
```markdown
```
or
```markdown
![alt_text][img_id]
...
[img_id]:/path/to/image "Some title text"
```
or
```markdown
[![alt text][img_id]][lnk_id]
...
[img_id]:path/to/image "Some title text"
[lnk_id]:path/to/page
```
etc.

Tested in chromium, chrome, firefox, electron on linux

**P.S.**\
The link hints work fine.

---

Example code:
```markdown
[![Google search][img_id]][lnk_id]

[img_id]:https://www.google.ru/images/branding/googlelogo/2x/googlelogo_color_160x56dp.png "Search in google"
[lnk_id]:https://google.com/
```

Screenshot:


---

My configuration:

```sh
$ uname -srm
```
>Linux 5.10.23-1-MANJARO x86_64

```sh
$ google-chrome-stable --version
```
>Google Chrome 89.0.4389.90

```sh
$ firefox --version
```
>Mozilla Firefox 86.0.1

```sh
$ electron --version
```
>v11.3.0

```sh
$ nvim --version
```
>NVIM v0.4.4\
>Build type: Release\
>LuaJIT 2.0.5\
>Compilation: /usr/bin/cc -D_FORTIFY_SOURCE=2 -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -O2 -DNDEBUG -DMIN_LOG_LEVEL=3 -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wshadow -Wconversion -Wmissing-prototypes -Wimplicit-fallthrough -Wvla -fstack-protector-strong -fno-common -fdiagnostics-color=always -DINCLUDE_GENERATED_DECLARATIONS -D_GNU_SOURCE -DNVIM_MSGPACK_HAS_FLOAT32 -DNVIM_UNIBI_HAS_VAR_FROM -I/build/neovim/src/build/config -I/build/neovim/src/neovim-0.4.4/src -I/usr/include -I/build/neovim/src/build/src/nvim/auto -I/build/neovim/src/build/include\
>Compiled by builduser
>
>Features: +acl +iconv +tui\
>See ":help feature-compile"
>
> system vimrc file: "$VIM/sysinit.vim"\
> fall-back for $VIM: "/usr/share/nvim"
>
>Run :checkhealth for more info